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Distal-less homeobox-1 (DLX1) is a well-established non-invasive biomarker for prostate cancer (PCa) diagnosis, however, its mechanistic underpinnings in disease pathobiology are not known. Here, we reveal the oncogenic role of DLX1 and show that abrogating its function leads to reduced tumorigenesis and metastases. We observed that ~60% of advanced-stage and metastatic patients display higher DLX1 levels. Moreover, ~96% of TMPRSS2-ERG fusion-positive and ~70% of androgen receptor (AR)-positive patients show elevated DLX1, associated with aggressive disease and poor survival. Mechanistically, ERG coordinates with enhancer-bound AR and FOXA1 to drive transcriptional upregulation of DLX1 in ERG-positive background. However, in ERG-negative context, AR/AR-V7 and FOXA1 suffice to upregulate DLX1. Notably, inhibiting ERG/AR-mediated DLX1 transcription using BET inhibitor (BETi) or/and anti-androgen drugs reduce its expression and downstream oncogenic effects. Conclusively, this study establishes DLX1 as a direct-target of ERG/AR with an oncogenic role and demonstrates the clinical significance of BETi and anti-androgens for DLX1-positive patients., Distal-less homeobox 1 (DLX1) is reported as a prostate cancer (PCa) diagnostic biomarker, but the mechanism for its upregulation in PCa is unclear. Here the authors show that ERG, AR and FOXA1 transcriptionally regulates DLX1 expression in PCa, and the inhibition of this ERG/AR transcriptional circuitry with a BET inhibitor reduces the oncogenic effects of DLX1.

Background We recently described a novel form of focal therapy for prostate cancer (CaP)-the precision prostatectomy. Here we report on the first 25 consecutive patients. Further, utilizing Surveillance Epidemiology and End Results (SEER)-registry data, we assess long-term oncological efficacies of various focal therapy techniques. Methods Men who met the criteria: (I) PSA ≤15 ng/mL, (II) stage ≤cT2, (III) dominant unilateral lesion with Gleason ≤4+3 with any number or percentage (%) of cores involved ipsilaterally on biopsy, (IV) no primary Gleason ≥4 contralaterally, and (V) preoperative erectile function score (IIEF-5/SHIM) of ≥17 with/without PDE-5i were included in this prospective, single-arm, IDEAL stage 2b study (December 2016 to July 2017). Safety of the technique, and intermediate-term urinary, sexual and oncological outcomes were studied. Descriptive statistics and Kaplan-Meier (KM) analysis were used to assess 12-month urinary continence (0-1 pad), 12-month sexual potency (SHIM ≥17), and 36-month freedom from clinically-significant CaP (grade group ≥2), radical treatment, metastatic disease and mortality. SEER-registry was queried to evaluate CaP-specific survival in patients undergoing hyperthermia, cryotherapy, or segmental prostatectomy. Results At study entry, the median (IQR) age, PSA and SHIM score were 56.5 (53.1-62.3) years, 4.2 (3.8-5.9) ng/mL and 23 [20-25], respectively. Only 1 patient met the Epstein criteria for active surveillance. All patients were followed for a minimum of 2 years. At 12 months, from a functional standpoint, all patients were continent. Twenty-three (92%) patients were potent at 12 months. From an oncological standpoint, at 36 months, the KM analysis (95% CI) demonstrated a 96.2% (92.9-98.7) rate of freedom from clinically-significant CaP and a 92.7% (88.9-97.2) rate of freedom from radical treatment. All patients were alive and free of metastatic disease at the latest follow-up. Analysis of the SEER-registry data demonstrated 10-year CaP-specific survival rates of 91.6% to 97.7% among the 3 studied modalities, P=0.298. Conclusions Precision prostatectomy is feasible, technically safe, and offers excellent postoperative functional results. At 36 months of follow-up, the oncological outcomes and secondary procedure rates appear to be at-par with the ablative forms of focal therapy.

Growth and differentiation factor 15 (GDF‐15), also known as macrophage inhibitory cytokine 1 (MIC‐1), may act as both a tumor suppressor and promotor and, by regulating NF‐κB and macrophage signaling, promote early prostate carcinogenesis. To determine whether expression of these two inflammation‐related proteins affect prostate cancer susceptibility, dual immunostaining of benign prostate biopsies for GDF‐15 and NF‐κB was done in a study of 503 case‐control pairs matched on date, age, and race, nested within a historical cohort of 10,478 men. GDF‐15 and NF‐κB expression levels were positively correlated (r = 0.39; p, In benign prostate biopsies we found expression of GDF‐15 and NF‐κB were positively correlated and lower in African American compared with white men. Prostate cancer risk estimates, however, suggest that NF‐κB and GDF‐15 expression exert opposite effects on prostate tumor development.

Objectives We present postprostatectomy pathology results from a series of prostate cancer (Pca) Gleason grade group ≥2 patients who did not have findings suggestive of cancer on preoperative pelvic magnetic resonance imaging (MRI). Methods We performed an institutional retrospective study of prostate magnetic resonance imaging (MRI) examinations done from October 2015 to February 2018. We identified patients who underwent prostatectomy for Pca Gleason ≥3 + 4 diagnosed on prostate biopsy with no associated MRI findings suggestive of malignancy and analyzed their postprostatectomy pathologic findings and MRI imaging results. Results At our institution, 850 men with Pca received MRI between 2015 and 2018, and 156/850 patients received robotic-assisted radical prostatectomy. Thirty-three patients (33/156 = 21%) had negative MRI for PIRAD 3 or greater but had a biopsy showing significant Pca. Their mean (range) age was 62.7 (50-86) years. Their median (interquartile range) PSA, and PSA density were, 4.6 (3.7) ng/mL and 0.12 (0.05) ng/mL/cm2, respectively; all not significantly different from patients with visible lesions on MRI who underwent surgery. On post prostatectomy pathology, 27/33 (82%) men had Pca Gleason score 7 or greater. The most common pattern was infiltrative growth with cancer glands intermingling between benign glands. Conclusion We describe the pathologic and imaging findings in an extensive series of men with clinically significant Pca with no significant lesions on preoperative MRI. Our results support the importance of patient counseling on the risk of missing significant Pca on MRI in isolation from other clinical variables.

Prostate cancer is frequently multifocal. Although there may be morphological variation, the genetic underpinnings of each tumor are not clearly understood. To assess the inter and intra tumor molecular heterogeneity in prostate biopsy samples, we developed a combined immunohistochemistry and RNA in situ hybridization method for the simultaneous evaluation of ERG, SPINK1, ETV1, and ETV4. Screening of 601 biopsy cores from 120 consecutive patients revealed multiple alterations in a mutually exclusive manner in 37% of patients, suggesting multifocal tumors with considerable genetic differences. Furthermore, the incidence of molecular heterogeneity was higher in African Americans patients compared to Caucasian American patients. About 47% of the biopsy cores with discontinuous tumor foci showed clonal differences with distinct molecular aberrations. ERG positivity occurred predominantly in low Gleason grade cancer, whereas ETV4 expression was observed mostly in high Gleason grade cancer. Further studies revealed correlation between the incidence of molecular markers and clinical and pathologic findings, suggesting potential implications for diagnostic pathology practice, such as defining dominant tumor nodules and discriminating juxtaposed but molecularly different tumors of different grade patterns.

M2 (tumor-supportive) macrophages may upregulate growth differentiation factor 15 (GDF15), which is highly expressed in prostate tumors, but the combined utility of these markers as prognostic biomarkers are unclear. We retrospectively studied 90 prostate cancer cases that underwent radical prostatectomy as their primary treatment and were followed for biochemical recurrence (BCR). These cases also had a benign prostate biopsy at least 1 year or more before their prostate cancer surgery. Using computer algorithms to analyze digitalized immunohistochemically stained slides, GDF15 expression and the presence of M2 macrophages based on the relative density of CD204- and CD68-positive macrophages were measured in prostate: (i) benign biopsy, (ii) cancer and (iii) tumor-adjacent benign (TAB) tissue. Both M2 macrophages (P = 0.0004) and GDF15 (P < 0.0001) showed significant inter-region expression differences. Based on a Cox proportional hazards model, GDF15 expression was not associated with BCR but, in men where GDF15 expression differences between cancer and TAB were highest, the risk of BCR was significantly reduced (hazard ratio = 0.26; 95% confidence interval = 0.09–0.94). In addition, cases with high levels of M2 macrophages in prostate cancer had almost a 5-fold increased risk of BCR (P = 0.01). Expression of GDF15 in prostate TAB was associated with M2 macrophage levels in both prostate cancer and TAB and appeared to moderate M2-macrophage-associated BCR risk. In summary, the relationship of GDF15 expression and CD204-positive M2 macrophage levels is different in a prostate tumor environment compared with an earlier benign biopsy and, collectively, these markers may predict aggressive disease.

We recently proposed that an epithelial renal tumor “papillary renal neoplasm with reverse polarity” represents a distinct entity. It constituted 4% of previously diagnosed papillary renal cell carcinoma at the participating institutions. Histologically, it is characterized by papillary or tubulopapillary architecture covered by a single layer of eosinophilic cells with finely granular cytoplasm and apically located nuclei. It is characteristically positive for GATA3 and L1CAM and lack vimentin and, to a lesser extent, α-methylacyl-CoA-racemase (AMACR/p504s) immunostaining. To investigate the molecular pathogenesis of these tumors, we performed targeted next-generation sequencing on ten previously reported papillary renal neoplasms with reverse polarity, followed by a targeted polymerase chain reaction analysis for KRAS mutations in a control series of 30 type 1 and 2 papillary renal cell carcinomas. KRAS missense mutations were identified in eight of ten papillary renal neoplasms with reverse polarity. These mutations were clustered in exon 2—codon 12: c.35 G > T (n = 6) or c.34 G > C (n = 2) resulting in p.Gly12Val and p.Gly12Arg alterations, respectively. One of the wild-type tumors had BRAF c.1798_1799delGTinsAG (p.Val600Arg) mutation. No KRAS mutations were identified in any of the 30 control tumors. In summary, this study supports our proposal that papillary renal neoplasm with reverse polarity is an entity distinct from papillary renal cell carcinoma and the only renal cell neoplasm to consistently harbor KRAS mutations.

Renal cell tumors with mixed morphology resembling multiple renal cell carcinoma (RCC) subtypes are generally regarded as unclassified RCC. However, occasionally, papillary adenoma or RCC appears admixed with a larger, different tumor histology. We retrieved 17 renal tumors containing a papillary adenoma or papillary RCC component admixed with another tumor histology and studied them with immunohistochemistry and fluorescence in situ hybridization (FISH). Larger tumors were oncocytomas (n = 10), chromophobe RCCs (n = 5), borderline oncocytic tumor (n = 1), and clear cell RCC (n = 1). The size of papillary component ranged from 1 to 34 mm. One tumor was an oncocytoma encircled by a cyst (2.0 cm) with papillary hyperplasia of the lining. The papillary lesions were diffusely cytokeratin 7 positive (17/17), in contrast to “host” tumors. Alpha-methylacyl-coA-racemase labeling was usually stronger in the papillary lesions (13/15). KIT was negative in all papillary lesions and the clear cell RCC and positive in 16/16 oncocytic or chromophobe tumors. Eight of 15 (53%) collision tumors had differing FISH results in the two components. A papillary renal cell proliferation within another tumor is an uncommon phenomenon with predilection for oncocytoma and chromophobe RCC, possibly related to their common entrapment of benign tubules. When supported by distinct morphology and immunohistochemistry in these two components, this phenomenon should be diagnosed as a collision of two processes. A diagnosis of unclassified RCC should be avoided, due to potential misrepresentation as an aggressive renal cancer.

We evaluated the clinicopathologic and chromosomal characteristics of a distinct subset of papillary renal tumors and compared them to a control series of papillary renal cell carcinoma types 1 and 2. Of the 18 patients, 9 were women and 9 were men, ranging in age from 46 to 80 years (mean, 64 y; median, 66 y). The tumors ranged in diameter from 0.6 to 3 cm (mean, 1.63 cm; median, 1.4 cm). Fourteen tumors were WHO/ISUP grade 2 and 4 were grade 1. All were stage category pT1. The tumors had branching papillae with thin fibrovascular cores, covered by cuboidal to columnar cells with granular eosinophilic cytoplasm, smooth luminal borders, and mostly regular and apically located nuclei with occasional nuclear clearing and inconspicuous nucleoli. Tubule formation and clear cytoplasmic vacuoles were observed in 5 and 9 tumors, respectively. Ten tumors had pseudocapsules. Psammoma bodies, necrosis, mitotic figures and intracellular hemosiderin are absent from all tumors. In contrast, papillary renal cell carcinoma type 1 consisted of delicate papillae covered by a single layer of cells with scanty pale cytoplasm with nuclei generally located in a single layer on the basement membrane of the papillary cores, while type 2 tumors had broad papillae covered by pseudostratified cells with eosinophilic cytoplasm and more randomly located nuclei. Both had occasional psammoma bodies, foamy macrophages and intracellular hemosiderin. Immunohistochemically, all were positive for pancytokeratin AE1/AE3, epithelial membrane antigen, MUC1, CD10, GATA3, and L1CAM. Cytokeratin 7 was positive in 16 tumors (1 had5% positivity). CD117 and vimentin were always negative. α-methylacyl-CoA-racemase (AMACR/p504s) showed variable staining (range, 10% to 80%) in 5 tumors. However, all tumors in the control group were negative for GATA3 and positive for AMACR/p504s and vimentin immunostains. Fluorescence in situ hybridization analysis of the study group demonstrated chromosome 7 trisomy in 5 tumors (33%), trisomy 17 in 5 tumors (33%), and trisomy 7 and 17 in 3 tumors (20%). Chromosome Y deletion was found in 1 of 7 male patients and chromosome 3p was present in all tumors. No tumor recurrence or metastasis occurred. In summary, we propose the term papillary renal neoplasm with reverse polarity for this entity.

BACKGROUND: Rising prostate-specific antigen (PSA) levels are associated with both increased risk of prostate cancer and prostatic inflammation. The confounding effects of inflammation on the utility of PSA kinetics to predict prostate cancer may be partially mitigated by anti-inflammatory drug use. We investigated the influence of anti-inflammatory drug use on the association of PSA kinetics with prostate cancer risk. METHODS: We studied 488 prostate cancer case-control pairs (290 white, 198 African American (AA)) nested in a retrospective cohort of men with a benign prostate biopsy. A series of multivariable models estimated prostate cancer risk associated with PSA velocity (PSAV) at different levels of anti-inflammatory drug use while adjusting for the presence of both clinical and histologic prostatitis. RESULTS: In men with one, two, or three or more courses of anti-inflammatory drug use, for each ng/mL/year increase in PSAV, prostate cancer risk increased 1.21-fold, 1.83-fold, and 1.97-fold, respectively (P < 0.0001). In controls with histologic prostatitis, anti-inflammatory drug use was associated with a significantly lower PSAV (P < 0.0001). This association was not observed in men with histologic prostatitis who were subsequently diagnosed with prostate cancer. A positive interaction between anti-inflammatory drug use and PSAV-associated prostate cancer risk was only observed in AA men, as well as a strong positive association between any anti-inflammatory drug use and clinical prostatitis (P = 0.004). CONCLUSIONS: In men with benign prostate biopsy, accounting for the presence of histologic prostatitis and anti-inflammatory drug use, particularly in AA men, may help distinguish between men with rising PSA because of prostatitis vs undiagnosed cancer.

Progressive multifocal leukoencephalopathy (PML) is a rare demyelinating disease caused by reactivation of John Cunningham virus affecting typically subcortical and periventricular white matter of immunocompromised hosts (human immunodeficiency virus infection, hematologic malignancies). Cerebral hemispheric white matter is most commonly affected by lytic infections, leading to progressive damage to oligodendrocytes in the central nervous system. Neuroimaging usually highlights scattered foci of white matter hypodensity not attributable to contrast enhancement or mass effect. In contrast, we present an unusual case of PML predominantly affecting cervical spinal cord and brainstem in an immunocompetent host. This is a rare subset of PML case that can occur in association with connective tissue disorders (Sjogren Syndrome in this case), systemic lupus erythematosus being the most common. Progressive multifocal leukoencephalopathy should be considered in the differential diagnosis of spinal cord or brainstem lesions, particularly in the patients with connective tissue disorders.

Systemic inflammation may increase risk for prostate cancer progression, but the role it plays in prostate cancer susceptibility is unknown. From a cohort of over 10,000 men who had either a prostate biopsy or transurethral resection that yielded a benign finding, we analyzed 517 incident prostate cancer cases identified during follow-up and 373 controls with one or more white blood cell tests during a follow-up period between one and 18 years. Multilevel, multivariable longitudinal models were fit to two measures of systemic inflammation, neutrophil-to-lymphocyte ratio (NLR) and monocyte-to-lymphocyte ratio (MLR), to determine NLR and MLR trajectories associated with increased risk for prostate cancer. For both measures, we found no significant differences in the trajectories by case/control status, however in modeling NLR trajectories there was a significant interaction between race (white or Black and case-control status. In race specific models, NLR and MLR values were consistently higher over time among white controls than white cases while case-control differences in NLR and MLR trajectories were not apparent among Black men. When cases were classified as aggressive as compared to non-aggressive, the case-control differences in NLR and MLR values over time among white men were most apparent for non-aggressive cases. For NLR among white men, significant case-control differences were observed for the entire duration of observation for men who had inflammation in their initial prostate specimen. It is possible that, among white men, monitoring of NLR and MLR trajectories after an initial negative biopsy may be useful in monitoring prostate cancer risk.

Nearly half of the prostate cancer (PCa) cases show elevated levels of ERG oncoprotein due toTMPRSS2-ERGgene fusion. Here, we demonstrate ERG mediated upregulation of Distal-less homeobox-1 (DLX1), an established PCa biomarker. Using series of functional assays, we show DLX1 elicits oncogenic properties in prostate epithelial cells, and abrogating its function leads to reduced tumor burden in mouse xenografts. Clinically, ∼60% of the PCa patients exhibit high DLX1 levels, while ∼50% of these cases also harbor elevated ERG associated with aggressive disease and poor survival probability. Mechanistically, we show that ERG gets recruited ontoDLX1promoter and interacts with its enhancer-bound androgen receptor (AR) and FOXA1 to regulateDLX1expression inTMPRSS2-ERGpositive cases. Alternatively, in ERG-negative cases, DLX1 is regulated by AR/AR-V7 and FOXA1. Importantly, BET bromodomain inhibitors disrupt the transcriptional regulators ofDLX1and its associated oncogenic properties, signifying their efficacy in treatment of DLX1-positive PCa patients.

Cystic trophoblastic tumor (CTT) is an uncommon trophoblastic proliferation of germ cell tumor origin, mostly reported in post-chemotherapy metastases of testicular germ cell tumors and rarely primary untreated testicular tumors. To date, we are not aware of occurrence in a non-testicular tumor. A 12-year-old boy presented with limb swelling, increased appetite, weight gain, and precocious puberty. Evaluation revealed right frontal lobe mass and elevated α-fetoprotein and β-human chorionic gonadotrophin. After response to neoadjuvant chemotherapy, the tumor was resected. Microscopically, the resection contained predominantly smooth muscle tissue with scattered small foci of glandular teratoma and CTT. Immunohistochemistry (SALL4, glypican 3) revealed no residual yolk sac tumor. Fluorescence in situ hybridization revealed gain of chromosome 12p. The patient has been disease-free for 13 years. This report expands the spectrum of primary central nervous system germ cell tumors with the occurrence of CTT in this site.

Aims To evaluate the molecular underpinnings of the rare aggressive prostate cancer variants adenosquamous carcinoma, pleomorphic giant-cell carcinoma, and sarcomatoid carcinoma. Methods and results We retrieved 19 tumours with one or more variant(s), and performed ERG immunohistochemistry, a next-generation sequencing assay targeting recurrent gene fusions, and fluorescence in-situ hybridisation (FISH) for ERG and BRAF. Divergent differentiation included: sarcomatoid carcinoma (n = 10), adenosquamous carcinoma (n = 7), and pleomorphic giant-cell carcinoma (n = 7). Five patients had more than one variant. Four had variants only in metastases. ERG rearrangement was detected in nine (47%, seven via sequencing, showing TMPRSS2-ERG fusions and one GRHL2-ERG fusion, and two via FISH, showing rearrangement via deletion). ERG was immunohistochemically positive in the adenocarcinoma in eight of nine (89%) patients, but was immunohistochemically positive in the variant in only five of nine patients (56%, typically decreased). One patient had a false-positive ERG immunohistochemical result in the sarcomatoid component despite a negative FISH result. Two (11%) harboured BRAF fusions (FAM131A-BRAF and SND1-BRAF). Conclusions ERG fusions are present in these rare prostate cancer variants with a frequency close to that in conventional prostate cancer (9/19, 47%). ERG immunohistochemistry usually detects rearrangement in the adenocarcinoma, but is less sensitive for the variant histology, with weak to negative staining. Adenosquamous and sarcomatoid variants can, particularly, occur together. Molecular assessment may be an additional tool in selected cases to confirm the prostatic origin of unusual tumours. The presence of two BRAF rearrangements suggests that this gene fusion may be enriched in this setting, as RAF kinase fusions have been previously reported in 1-2% of prostate cancers.

Emergence of an aggressive androgen receptor (AR)-independent neuroendocrine prostate cancer (NEPC) after androgen-deprivation therapy (ADT) is well-known. Nevertheless, the majority of advanced-stage prostate cancer patients, including those with SPINK1-positive subtype, are treated with AR-antagonists. Here, we show AR and its corepressor, REST, function as transcriptional-repressors of SPINK1, and AR-antagonists alleviate this repression leading to SPINK1 upregulation. Increased SOX2 expression during NE-transdifferentiation transactivates SPINK1, a critical-player for maintenance of NE-phenotype. SPINK1 elicits epithelial-mesenchymal-transition, stemness and cellular-plasticity. Conversely, pharmacological Casein Kinase-1 inhibition stabilizes REST, which in cooperation with AR causes SPINK1 transcriptional-repression and impedes SPINK1-mediated oncogenesis. Elevated levels of SPINK1 and NEPC markers are observed in the tumors of AR-antagonists treated mice, and in a subset of NEPC patients, implicating a plausible role of SPINK1 in treatment-related NEPC. Collectively, our findings provide an explanation for the paradoxical clinical-outcomes after ADT, possibly due to SPINK1 upregulation, and offers a strategy for adjuvant therapies., SPINK1 upregulation is found in ~10–25% of prostate cancers. Here, they show that whilst SPINK1 is transcriptionally repressed by androgen receptor and its co-repressor REST, it is upregulated after androgen-deprivation therapy, which leads to neuroendocrine differentiation of prostate cancer cells.

Staging criteria for renal cell carcinoma differ from many other cancers, in that renal tumors are often spherical with subtle, finger-like extensions into veins, renal sinus, or perinephric tissue. We sought to study interobserver agreement in pathologic stage categories for challenging cases. An online survey was circulated to urologic pathologists interested in kidney tumors, yielding 89% response (31/35). Most questions included 1 to 4 images, focusing on: vascular and renal sinus invasion (n=24), perinephric invasion (n=9), and gross pathology/specimen handling (n=17). Responses were collapsed for analysis into positive and negative/equivocal for upstaging. Consensus was regarded as an agreement of 67% (2/3) of participants, which was reached in 20/33 (61%) evaluable scenarios regarding renal sinus, perinephric, or vein invasion, of which 13/33 (39%) had ≥80% consensus. Lack of agreement was especially encountered regarding small tumor protrusions into a possible vascular lumen, close to the tumor leading edge. For gross photographs, most were interpreted as suspicious but requiring histologic confirmation. Most participants (61%) rarely used special stains to evaluate vascular invasion, usually endothelial markers (81%). Most agreed that a spherical mass bulging well beyond the kidney parenchyma into the renal sinus (71%) or perinephric fat (90%) did not necessarily indicate invasion. Interobserver agreement in pathologic staging of renal cancer is relatively good among urologic pathologists interested in kidney tumors, even when selecting cases that test the earliest and borderline thresholds for extrarenal extension. Disagreements remain, however, particularly for tumors with small, finger-like protrusions, closely juxtaposed to the main mass.

Aims Pseudosarcomatous myofibroblastic proliferations of the genitourinary tract have a debatable relationship with inflammatory myofibroblastic tumour (generally lacking ALK rearrangement); however, they share several overlapping features with nodular fasciitis of soft tissue. As rearrangement of the USP6 gene has been recently recognised as a recurrent alteration in soft tissue nodular fasciitis, and several other alternative gene fusions have been recently recognised in inflammatory myofibroblastic tumour, the aim of this study was to investigate whether USP6, ROS1 or ETV6 rearrangements were present in these lesions (12 cases). Methods and results Fluorescence in-situ hybridisation analysis was performed by the use of bacterial artificial chromosome-derived break-apart probes against USP6, ROS1, and ETV6. Two cases with adequate genetic material from recent paraffin tissue blocks were also tested by use of a solid tumour gene fusion detection assay via next-generation sequencing, targeting >50 known genes involved in recurrent fusions. None of the genitourinary pseudosarcomatous myofibroblastic proliferations was found to harbour USP6 (0/12), ROS1 (0/8) or ETV6 (0/7) rearrangements, and no gene fusions were detected in two cases studied by sequencing. Conclusions Despite overlap in histological and immunohistochemical features between pseudosarcomatous myofibroblastic proliferation and nodular fasciitis, these tumours lack the recently recognised USP6 rearrangements that occur in nodular fasciitis, as well as alternative fusions found in ALK-negative inflammatory myofibroblastic tumours. At present, this diagnosis remains based primarily on clinical, histological and immunohistochemical features.

Occasionally, renal cell carcinoma (RCC) with renal vein extension spreads against the flow of blood within vein branches into the kidney, forming multifocal nodules throughout the renal parenchyma. These foci are not regarded as multiple tumors but rather reverse spread of tumor along the venous system. This intravascular spread has previously been reported in clear cell RCC and RCC unclassified. However, to our knowledge, this has never been reported in chromophobe RCC. Chromophobe RCC is a unique histologic subtype of renal cancer, generally thought to have less aggressive behavior. However, it nonetheless has the potential to undergo sarcomatoid dedifferentiation, which is associated with poor prognosis. We report a unique case of a 65-year-old man with chromophobe RCC (pT3a) showing classic morphology (nonsarcomatoid), yet presenting with retrograde venous invasion and hilar lymph node metastasis at the time of right radical nephrectomy. Fluorescence in situ hybridization revealed gain of chromosome 21 with loss of multiple other chromosomes. Partial hepatectomy was performed to resect metastatic RCC 7 months after nephrectomy, revealing chromophobe RCC with classic morphology. Bone biopsy confirmed skeletal metastases 38 months after initial diagnosis. Although invasion of the renal vein and retrograde venous invasion are characteristically seen in clear cell RCC, this unusual phenomenon may also occur in chromophobe RCC, despite its unique tumor biology. This and gain of chromosome 21, which was postulated to be associated with aggressive behavior in a previous report, were associated with adverse behavior in our patient, who had short-term progression to multi-organ metastatic disease.

Aims To further characterise biphasic squamoid renal cell carcinoma (RCC), a recently proposed variant of papillary RCC. Methods and results We identified 28 tumours from multiple institutions. They typically showed two cell populations-larger cells with eosinophilic cytoplasm and higher-grade nuclei, surrounded by smaller, amphophilic cells with scanty cytoplasm. The dual morphology was variable (median 72.5% of tumour, range 5-100%); emperipolesis was found in all cases. The male/female ratio was 2:1, and the median age was 55 years (range 39-86 years). The median tumour size was 20 mm (range 9-65 mm). Pathological stage pT1a was found in 21 cases, pT1b in three, and pT3a and pT3b in one each (two not available). Multifocality was found in 32%: multifocal biphasic RCC in one case, biphasic + papillary RCC in two cases, biphasic + clear cell RCC in three cases, biphasic + low-grade urothelial carcinoma of the renal pelvis in one case, and biphasic + Birt-Hogg-Dube syndrome in one case. Positive immunostains included: PAX8, cytokeratin (CK) 7, α-methylacyl-CoA racemase, epithelial membrane antigen, and vimentin. Cyclin D1 was expressed only in the larger cells. The Ki67 index was higher in the larger cells (median 5% versus ≤1%). Negative stains included: carbonic anhydrase 9, CD117, GATA-3, WT1, CK5/6, and CK20; CD10 and 34βE12 were variably expressed. Gains of chromosomes 7 and 17 were found in two evaluated cases. Follow-up was available for 23 patients (median 24 months, range 1-244 months): 19 were alive without disease, one was alive with recurrence, and one had died of disease (two had died of other causes). Conclusions Biphasic papillary RCC is a rare variant of papillary RCC, and is often multifocal.

Objective We assessed the prognostic value of histomorphologic features of lymph node (LN) metastases in patients with prostate cancer treated with radical prostatectomy Materials and Methods We evaluated the effect of the features of LN metastasis on the risk of biochemical recurrence (BCR) in 280 LN-positive patients who underwent radical prostatectomy between 2006 to 2018. LN specific parameters recorded included number of metastatic LNs, size of the largest metastatic focus, Gleason Grade (GG) of the metastatic focus, and extranodal extension (ENE). Results A solitary positive LN was found in 166/280 (59%), 95/280 (34%) patients had 2-4 positive LNs, and 19/280 (7%) had 5 or more positive LNs. The size of the largest metastatic focus > 2 mm (macrometastasis) in 154/261 (59%). GG of the metastatic focus was as follows: GG 1-2: 29/224 (13%); GG 3: 27/224 (12%); and GG 4-5: 168/224 (75%). ENE was identified in 99/244 (41%). We found the number of LNs positive (2-4 vs. 1 Hazard ratio (HR) = 1.60; 95% CI: 1.02 to 2.5; P = 0.04) and GG of the metastatic focus (GG 4&5 vs. 1-3 HR = 1.90; 95% CI: 1.14-3.2; P= 0.014) to be independent predictors of the risk of BCR after surgery on multivariate analysis. Conclusions Our study showed the number of LNs positive and GG of the LN metastatic focus to be significant independent predictors of BCR after radical prostatectomy. We recommend reporting histomorphologic parameters of LN metastasis as they may help in defining BCR risk categorization.

DNA methylation is a known regulator of mRNA expression. Recent studies in cancer have shown that significant proportions of the variability in mRNA expression can be explained by variation in DNA methylation. However, none of these studies have investigated the influence of race on this relationship. Here, we develop poly-CpG site models of gene expression that facilitate the quantification of race-specific effects on the regulatory connection between methylation and transcriptional gene expression. Paired Illumina 450k methylation and RNA-Seq gene expression data from The Cancer Genome Atlas (TCGA) was used to develop poly-CpG site elastic net penalized Poisson regression models of gene expression that account for race-by-CpG interactions for each of the eight TCGA tumor types with African American (AA) representation (>40 tumors each). Race-specific effects were summarized as the percentage of CpGs in a gene model with retained interaction terms. The method was applied to methylation data from an AA radical prostatectomy prostate cancer cohort (n=261) to generate predicted gene expression estimates that were used to perform a mechanistic epigenome-wide association study (EWAS) of Gleason grade (≤3+4 and ≥4+3 tumors). High percentages of variability in mRNA expression can be explained by poly-CpG site models, incorporating race specific effects, with tumor type ranges of 62-90% overall, 64-87% for AAs, and 64-92% for European Americans (EAs). Race played a significant role in the relationship between methylation and mRNA expression, with 86-97% of gene models containing at least one CpG site with a race-specific effect. Further, the median percentage of CpGs in a gene model with race-specific effects ranging from 11-18%. For these race-specific effects, the vast majority (>99%) had the same direction of association between the CpG site and gene expression in both AAs and EAs but with differing magnitudes. Application of this approach identified unique methylation alterations (97%) associated with Gleason grade compared with single site and comb-p region-based EWAS. In summary, this poly-CpG site modelling approach revealed a significant impact of race in the regulatory relationship between methylation and gene expression. The high percentage of genes -and CpG sites within those genes- demonstrating race-specific effects was a general phenomenon observed across all eight tumor types investigated. In addition to revealing this previously underappreciated contribution of race, the application of the predicted gene expression output from these poly-CpG site models to perform a gene-based EWAS of Gleason grade demonstrated that it provides a) complementary information to commonly used EWAS methods and b) direct expression-based mechanistic interpretation of findings from an AA methylation-based EWAS of prostate cancer. Citation Format: Ian M. Loveless, Yalei Chen, Sudha Sadasivan, Indrani Datta, Nilesh Gupta, Pamela Paris, Jia Li, Benjamin A. Rybicki, Albert M. Levin. The impact of race on the relationship between poly-CpG DNA methylation and mRNA expression in cancer with application to epigenome-wide association studies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2100.

Telomere shortening is linked to aging and thought to be associated with increased risk for cancer. Most cancer studies have used leukocyte telomere length as a surrogate measure for telomere length with few focused upon telomeres in the target tissue of cancer origin. To determine whether telomere length in pre-malignant prostate tissue is associated with subsequent prostate cancer risk, we conducted a case-control study of 530 case-control pairs matched on date, age at cohort entry, and race nested within a historical cohort of 10,478 men with a benign prostate biopsy. Overall mean telomere length assessed using modified quantitative real-time PCR was not different in benign prostate biopsies of prostate cancer cases vs. matched controls (1.65 ± 0.35 vs. 1.64 ± 0.39; p=0.41). However, race was significantly associated with telomere length with African American (AA) men having shorter telomeres in benign prostate biopsy compared with white men (1.59 ± 0.37 vs. 1.70 ± 0.37; p Citation Format: Benjamin A. Rybicki, Sudha M. Sadasivan, Yalei Chen, Ian Loveless, Nilesh S. Gupta, Dhananjay A. Chitale, Sean R. Williamson, Andrew G. Rundle, Deliang Tang. Race differences in telomere length in benign prostate and subsequent risk of prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 750.

Clear cell renal cell carcinoma is by far the most common form of kidney cancer; however, a number of histologically similar tumors are now recognized and considered distinct entities. The Cancer Genome Atlas published data set was queried (http://cbioportal.org) for clear cell renal cell carcinoma tumors lacking VHL gene mutation and chromosome 3p loss, for which whole-slide images were reviewed. Of the 418 tumors in the published Cancer Genome Atlas clear cell renal cell carcinoma database, 387 had VHL mutation, copy number loss for chromosome 3p, or both (93%). Of the remaining, 27/31 had whole-slide images for review. One had 3p loss based on karyotype but not sequencing, and three demonstrated VHL promoter hypermethylation. Nine could be reclassified as distinct or emerging entities: translocation renal cell carcinoma (n=3), TCEB1 mutant renal cell carcinoma (n=3), papillary renal cell carcinoma (n=2), and clear cell papillary renal cell carcinoma (n=1). Of the remaining, 6 had other clear cell renal cell carcinoma-associated gene alterations (PBRM1, SMARCA4, BAP1, SETD2), leaving 11 specimens, including 2 high-grade or sarcomatoid renal cell carcinomas and 2 with prominent fibromuscular stroma (not TCEB1 mutant). One of the remaining tumors exhibited gain of chromosome 7 but lacked histological features of papillary renal cell carcinoma. Two tumors previously reported to harbor TFE3 gene fusions also exhibited VHL mutation, chromosome 3p loss, and morphology indistinguishable from clear cell renal cell carcinoma, the significance of which is uncertain. In summary, almost all clear cell renal cell carcinomas harbor VHL mutation, 3p copy number loss, or both. Of tumors with clear cell histology that lack these alterations, a subset can now be reclassified as other entities. Further study will determine whether additional entities exist, based on distinct genetic pathways that may have implications for treatment.

Context.— Urinary bladder flat carcinoma in situ (CIS) is a worrisome lesion, requiring aggressive surveillance and treatment. Cytokeratin 20 (CK20) and p53 are common immunohistochemical antibodies used to supplement CIS diagnosis in biopsy samples. However, existing data come primarily from unequivocally benign and malignant specimens. Objective.— To correlate these markers in specimens with borderline histology with outcomes. Design.— CK20 and p53 immunohistochemistry was analyzed for staining pattern, classified as CIS pattern (both stains yielding strong labeling of the area of concern), discordant (only 1 stain yielding CIS pattern), indeterminate (1 or both stains yielding partial or equivocal labeling), or benign (both stains yielding a benign pattern). Results.— Specimens with equivocal atypia (n = 69) from 65 patients were studied. There were 9 specimens (13%) that had a CIS staining pattern, 18 (26%) were discordant, 31 (45%) were indeterminate, and 11 (16%) were benign. Of the discordant specimens, 13 labeled for CK20 but not p53, whereas 5 showed the opposite. Most specimens (n = 47; 68%) were obtained from patients with a known history of bladder cancer, of which recurrence developed in 27, with an average interval of 37 months (range, 2–216 months). A subset (n = 22; 34%) had no prior history of bladder cancer, from which only 1 patient with CK20-positive/p53-equivocal staining later developed diagnostic carcinoma. Conclusions.— In our cohort of specimens with equivocal urothelial atypia, very few patients without a prior diagnosis of bladder cancer progressed to diagnostic cancer (1 of 22), suggesting that staining results should be interpreted with caution in de novo atypia. Patients with a known history of bladder cancer had a substantial rate of recurrence, independent of staining pattern.

Renal oncocytoma and chromophobe renal cell carcinoma have been long recognized as distinct tumors; however, it remains unknown if uniform diagnostic criteria are used to distinguish these tumor types in practice. A survey was distributed to urologic pathologists regarding oncocytic tumors. Responses were received from 17 of 26 invitees. Histologically, more than 1 mitotic figure was regarded as most worrisome (n=10) or incompatible (n=6) with oncocytoma diagnosis. Interpretation of focal nuclear wrinkling, focal perinuclear clearing, and multinucleation depended on extent and did not necessarily exclude oncocytoma if minor. Staining techniques most commonly used included the following: cytokeratin 7 (94%), KIT (71%), vimentin (65%), colloidal iron (59%), CD10 (53%), and AMACR (41%). Rare cytokeratin 7-positive cells (≤5%) were regarded as most supportive of oncocytoma, although an extent excluding oncocytoma was not universal. Multiple chromosomal losses were most strongly supportive for chromophobe renal cell carcinoma diagnosis (65%). Less certainty was reported for chromosomal gain or a single loss. For tumors with mixed or inconclusive features, many participants use an intermediate diagnostic category (82%) that does not label the tumor as unequivocally benign or malignant, typically "oncocytic neoplasm" or "tumor" with comment. The term "hybrid tumor" was used variably in several scenarios. A slight majority (65%) report outright diagnosis of oncocytoma in needle biopsies. The morphologic, immunohistochemical, and genetic characteristics that define oncocytic renal tumors remain incompletely understood. Further studies correlating genetics, behavior, and histology are needed to define which tumors truly warrant classification as carcinomas for patient counseling and follow-up strategies.

Background Obesity is associated with risk of aggressive prostate cancer (PCa), but not with over-all PCa risk. However, obese men have larger prostates which may lower biopsy accuracy and cause a systematic bias toward the null in epidemiologic studies of over-all risk. Methods Within a cohort of 6692 men followed-up after a biopsy or transurethral resection of the prostate (TURP) with benign findings, a nested case-control study was conducted of 495 prostate cancer cases and controls matched on age, race, follow-up duration, biopsy versus TURP, and procedure date. Data on body mass index and prostate volume at the time of the initial procedure were abstracted from medical records. Results Prior to consideration of differences in prostate volume, overweight (OR = 1.41; 95%CI 1.01, 1.97), and obese status (OR = 1.59; 95%CI 1.09, 2.33) at the time of the original benign biopsy or TURP were associated with PCa incidence during follow-up. Prostate volume did not significantly moderate the association between body-size and PCa, however it did act as an inverse confounder; adjustment for prostate volume increased the effect size for overweight by 22% (adjusted OR = 1.52; 95%CI 1.08, 2.14) and for obese status by 23% (adjusted OR = 1.77; 95%CI 1.20, 2.62). Larger prostate volume at the time of the original benign biopsy or TURP was inversely associated with PCa incidence during follow-up (OR = 0.92 per 10 cc difference in volume; 95%CI 0.88, 0.97). In analyses that stratified case-control pairs by tumor aggressiveness of the case, prostate volume acted as an inverse confounder in analyses of non-aggressive PCa but not in analyses of aggressive PCa. Conclusions In studies of obesity and PCa, differences in prostate volume cause a bias toward the null, particularly in analyses of non-aggressive PCa. A pervasive underestimation of the association between obesity and overall PCa risk may exist in the literature.

Background Pan-cancer studies of somatic copy number alterations (SCNAs) have demonstrated common SCNA patterns across cancer types, but despite demonstrable differences in aggressiveness of some cancers by race, pan-cancer SCNA variation by race has not been explored. This study investigated a) racial differences in SCNAs in both breast and prostate cancer, b) the degree to which they are shared across cancers, and c) the impact of these shared, race-differentiated SCNAs on cancer survival. Methods Utilizing data from The Cancer Genome Atlas (TCGA), SCNAs were identified using GISTIC 2.0, and in each tumor type, differences in SCNA magnitude between African Americans (AA) and European Americans (EA) were tested using linear regression. Unsupervised hierarchical clustering of the copy number of genes residing in race-differentiated SCNAs shared between tumor types was used to identify SCNA-defined patient groups, and Cox proportional hazards regression was used to test for association between those groups and overall/progression-free survival (PFS). Results We identified SCNAs that differed by race in breast (n = 58 SCNAs; permutation p − 4) and prostate tumors (n = 78 SCNAs; permutation p = 0.006). Six race-differentiated SCNAs common to breast and prostate found at chromosomes 5q11.2-q14.1, 5q15-q21.1, 8q21.11-q21.13, 8q21.3-q24.3, 11q22.3, and 13q12.3-q21.3 had consistent differences by race across both tumor types, and all six were of higher magnitude in AAs, with the chromosome 8q regions being the only amplifications. Higher magnitude copy number differences in AAs were also identified at two of these race-differentiated SCNAs in two additional hormonally-driven tumor types: endometrial (8q21.3-q24.3 and 13q12.3-q21.3) and ovarian (13q12.3-q21.3) cancers. Race differentiated SCNA-defined patient groups were significantly associated with survival differences in both cancer types, and these groups also differentiated within triple negative breast cancers based on PFS. While the frequency of the SCNA-defined patient groups differed by race, their effects on survival did not. Conclusions This study identified race-differentiated SCNAs shared by two related cancers. The association of SCNA-defined patient groups with survival demonstrates the clinical significance of combinations of these race-differentiated genomic aberrations, and the higher frequency of these alterations in AA relative to EA patients may explain racial disparities in risk of aggressive breast and prostate cancer.

About half of the patients treated with docetaxel in the setting of metastatic castration-resistant prostate cancer (CRPC) are non-responders. Therefore, a marker of response would be beneficial for clinical decision-making. We evaluated class III β-tubulin (βIII-tubulin) expression as a predictor of resistance in this setting, which previously has been correlated with lack of response to taxanes in other cancers. Patients with CRPC were included if they were treated with at least 3 cycles of docetaxel between 1990 and 2011. βIII-tubulin expression was assessed by immunostaining, which was performed in tissue samples obtained either via biopsy or prostatectomy at the time of diagnosis. Rates of prostate-specific antigen (PSA) response and overall survival (OS) following docetaxel treatment were compared between patients with high (2+ or 3+ staining) vs. low (0 or 1+ staining) βIII-tubulin expression. Of 73 patients, 26 (35%) had a high expression of βIII-tubulin. A PSA decline of 10% or greater occurred in 65% of patients with a high βIII-tubulin expression vs. 89% with a low βIII-tubulin expression (p = 0.0267). The median OS for patients with a high βIII-tubulin expression was 17.4 (95% CI 8.7-21.0) months vs. 19.8 (95% CI 16.6-23.6) months for patients with a low expression (p = 0.039). Our results show that a high βIII-tubulin expression is a negative prognostic factor in metastatic CRPC patients treated with docetaxel.

Primary bladder paraganglioma is rare. A 57-year old man presented with a mass in the inferior wall of the bladder identified on computerized tomography imaging. We investigated the mass with office cystoscopy followed by transurethral resection, which was found to be a nonfunctioning paraganglioma. 68Ga-DOTA-conjugated somatostatin receptor-targeting peptide positron emission tomography revealed no other locations of the disease. The mass was then completely removed through robotic assisted partial cystectomy. Succinate dehydrogenase B immunohistochemistry was normal, arguing against a succinate dehydrogenase-deficient paraganglioma. Keywords: Bladder, Paraganglioma, Partial cystectomy

Background and Objective To determine the effect of multiplicity of prostate imaging reporting and data system assessment category 3 (PI-RADS 3) lesions on cancer detection rate (CDR) of confirmatory targeted biopsy of such lesion in patients diagnosed with prostate cancer and managed with active surveillance. Methods This study was conducted at a single academic institution. There were 91 men with ≥ 1 PI-RADS 3 lesion detected through magnetic resonance imaging (MRI) after systematic prostate biopsy in the course of management of patients diagnosed with prostate cancer with active surveillance. We compared the CDRs based on targeted biopsy of PI-RADS 3 lesions that occurred (1) as solitary lesions, (2) as 1 of multiple PI-RADS 3 only lesions, or (3) with ≥ 1 higher grade lesion. Results Median age was 65.0 years (interquartile range 59.5–70.0), median prostate specific antigen was 5.95 ng/ml (interquartile range 4.30–8.83), and median prostate specific antigen density was 0.161 ng/ml2 (0.071–0.194). Forty-three men had solitary PI-RADS 3 lesions, 22 had multiple PI-RADS 3 only lesions, and 26 had multiple lesions with ≥ 1 higher grade lesion. The overall CDR (Gleason score ≥ 3 + 3) based on confirmatory MRI targeted biopsy in a given PI-RADS 3 lesion in each group was 23%, 45%, and 54%, respectively (P = 0.0274). The CDRs for clinically significant disease (Gleason score ≥ 3 + 4) were 16%, 32%, and 35%, respectively (P = 0.1701). Conclusions Coexisting lesions increase the CDR of confirmatory MRI targeted biopsy of PI-RADS 3 lesions in patients managed with active surveillance. Risk stratification algorithms for PI-RADS 3 lesion to guide biopsy and management decisions may consider including multiplicity of lesions.

Expression profiles of erythroblast transformation-specific (ETS)-related gene fusions and serine protease inhibitor Kazal-type 1 (SPINK1) in early onset prostate cancer have not been thoroughly explored.We retrieved 151 radical prostatectomy specimens from young men with prostate cancer (55 years) and characterized the expression of ETS-related gene (ERG), SPINK1, ETS Variant 1 (ETV1), and ETV4 by dual immunohistochemistry and dual RNA in situ hybridization. Age, race, family history, preoperative prostate-specific antigen, biochemical recurrence, and pathological variables using whole-mount radical prostatectomy tissue were collected.A total of 313 tumor nodules from 151 men including 68 (45%) Caucasians and 61 (40%) African Americans were included in the analysis. Positive family history of prostate cancer was seen in 65 (43%) patients. Preoperative prostate-specific antigen ranged from 0.3 to 52.7 ng/mL (mean = 7.04). The follow-up period ranged from 1 to 123.7 months (mean = 30.3). Biochemical recurrence was encountered in 8 of 151 (5%). ERG overexpression was observed in 85 of 151 (56%) cases, followed by SPINK1 in 61 of 151 (40%), ETV1 in 9 of 149 (6%), and ETV4 in 4 of 141 (3%). There were 25 of 151 (17%) cases showing both ERG and SPINK1 overexpression within different regions of either the same tumor focus or different foci. Higher frequency of ERG overexpression was seen in younger patients (≤45 years old; 76% vs 49%, P = .002), Caucasian men (71% vs 41% P = .0007), organ-confined tumors (64% vs 33%, P = .0008), and tumors of Gleason Grade groups 1 and 2 (62% vs 26%, P = .009). SPINK1 overexpression was more in African American men (68% vs 26%, P = .00008), in tumors with high tumor volume (20%) and with anterior located tumors. ETV1 and ETV4 demonstrated rare overexpression in these tumors, particularly in the higher-grade tumors.This study expands the knowledge of the clonal evolution of multifocal cancer in young patients and support differences in relation to racial background and genetics of prostate cancer.

OBJECTIVE To compare the utility of the systematic 12-core prostate biopsy (SB) combined with magnetic resonance imaging (MRI)-targeted lesion biopsy (MRI-TB) vs MRI-TB alone in the diagnosis of high PI-RADS lesions. MATERIALS AND METHODS Patients undergoing MRI-TB + SB for suspicious MRI lesions were retrospectively reviewed. These patients had a previous prostate biopsy and were evaluated with MRI to assess the need for a repeat biopsy. Pathologic findings of MRI-TB combined with a SB were compared to those of the patients’ previous SB. An upgrade was defined as an increase in the Gleason Score of any prior biopsy. A no-upgrade (NU) MRI-TB was defined as a MRI-TB that did not lead to disease upgrading when compared to SB. RESULTS A total of 148 patients were analyzed in this study. Of the 255 total lesions (247 lesions with PI-RADS ≥3), 141 were upgraded from the previous biopsy (55.3%). Of these, 104 were upgraded by the MRI-TB (40.8%), and 87 lesions were upgraded by the SB (34.1%). The MRI-TB had a NU rate of 26.2% for all lesions. On subanalysis, the NU rates of PI-RADS 3, 4, and 5 MRI-TBs were 39.3%, 21.2%, and 3.4%, respectively. CONCLUSION The NU rate for the MRI-TB in a PIRADS-5 lesion is meager. Men with a PI-RADS 5 lesion may be safely managed with the MRI-TB alone without combining with SB. Men with PI-RADS 3 and 4 lesions should benefit from SB in addition to MRI-TB for accurate management of their disease.

Expression profiles of ETS related genes and SPINK1 in early onset prostate cancer have not been thoroughly explored. We retrieved 151 radical prostatectomy specimens from young men with prostate cancer (ETV1andETV4by dual immunohistochemistry and dual RNAin-situhybridization. Age, race, family history, preoperative prostate-specific antigen, biochemical recurrence and pathological variables using whole mount radical prostatectomy tissue were collected. 313 tumor nodules from 151 men including 68 (45%) Caucasians and 61 (40%) African Americans. Positive family history of prostate cancer was observed in 65 (43%) patients. Preoperative prostate-specific antigen ranged from 0.3 to 52.7 ng/ml (mean 7.04). Follow-up period ranged from 1 to 123.7 months (Mean 30.3). Biochemical recurrence was encountered in 8/151 (5%). ERG overexpression was observed in 85/151 (56%) cases, followed by SPINK1 in 61/151 (40%),ETV1in 9/149 (6%), andETV4in 4/141 (3%). There were 25/151 (17%) cases showing both ERG and SPINK1 overexpression within different regions of either the same tumor focus or different foci. Higher frequency of ERG overexpression was seen in younger patients (≤ 45 years old) (76% vs. 49%,p= 0.002213), Caucasian men (71% vs. 41%p= 0.000707), organ-confined tumors (64% vs. 33%,p= 0.00079), and tumors of Grade Groups 1 and 2 (62% vs. 26%,p= 0.008794). SPINK1 overexpression was more in African American men (68% vs. 26%,p= 0.00008), in tumors with high tumor volume (> 20%) and with anterior located tumors.ETV1andETV4demonstrated rare overexpression in these tumors, particularly in the higher-grade tumors. This study expands the knowledge of the clonal evolution of multifocal cancer in young patients and support differences in relation to racial background and genetics of prostate cancer.

Analysis of next generation transcriptome sequencing data of prostate cancer identified a novel gene fusion formed by the fusion of a protein coding gene (KLK4) with a non-coding pseudogene (KLKP1) and expression of its cognate protein. Screening of 659 prostate cancer TMA showed about 32% of positive cases predominantly expressed in higher Gleason grade tumors. Concomitant expression with ERG but not with SPINK1 and other ETS fusion positive tumors. Fusion gene expression potentially regulated by AR and ERG. Antibody specific to the KLK4-KLKP1 fusion protein was validated by immunohistochemistry and western blot methods. Oncogenic properties were validated by in vitro and in vivo functional studies. Clinical data analysis shows significant association with prostate cancer in young men and overall survival analysis indicate favorable prognosis. Non-invasive detection in urine samples has been confirmed. Taken together, we present a novel biomarker for routine screening of high Gleason grade prostate cancer at diagnosis.SIGNIFICANCEWe discovered and validated a novel prostate cancer (PCa) specific fusion gene involving a protein coding (KLK4) and a pseudogene (KLKP1) and its cognate protein. The unique feature of this fusion gene is the conversion of the noncoding pseudogene into a protein coding gene and its unique expression only in about 30% of high Gleason grade PCa. Expression of this gene is found to be concomitant in ERG fusion positive prostate cancer but mutually exclusive with SPINK1, ETV1, ETV4 and ETV5 positive tumors. Like other ETS family gene fusions, KLK4-KLKP1 can be detected in the urine samples of patients with prostate cancer enabling non-invasive detection of high Gleason grade prostate cancer. Given the unique feature of this fusion oncogenic potential, high Gleason grade specific expression and noninvasive detection, this novel gene fusion has a potential to be used as a biomarker for early detection of high-grade prostate cancer and a therapeutic target.

INTRODUCTION AND OBJECTIVES:Comedonecrosis has always been assigned Gleason pattern 5. Recent recommendations suggest against the grading of intraductal carcinoma. We hypothesized that prostatic adenocarcinoma with comedonecrosis may be frequently intraductal and therefore prostate cancer grading system may need to be revised.METHODS:We searched our pathology database from 2014-2018 for radical prostatectomy cases with documented comedonecrosis (specific grade patterns accounting for pattern 4 and 5 have been documented over this period). From an initial cohort of 52 cases with reported comedonecrosis, 40 cases were retrieved and had identifiable areas of comedonecrosis on additional whole mount slides prepared for immunohistochemistry. Immunohistochemical staining was performed for prostatic basal cell markers p63 and high molecular weight cytokeratin on whole-mount tumor blocks with the largest areas of comedonecrosis.RESULTS:In 24 cases (60%), the comedonecrosis was located only in intraductal carcinom...

INTRODUCTION AND OBJECTIVES:We previously presented post prostatectomy pathology results from a small number of prostate cancer (PCa) patients who did not have findings suggestive of cancer on pre-...

The Serine Peptidase Inhibitor, Kazal type 1 (SPINK1) overexpression represents ~10-25% of the prostate cancer (PCa) cases associated with shorter recurrence-free survival and poor prognosis. Nonetheless, androgen-deprivation therapy (ADT) remains the mainstay treatment for locally advanced and metastatic PCa patients. However, majority of these individuals eventually progress to castration-resistant stage, and a subset of these patients develop ADT-induced neuroendocrine PCa. Despite adverse effects of ADT, possible role of androgen signaling in SPINK1-mediated prostate oncogenesis remains unexplored. Here, we show that androgen receptor (AR) and its corepressor, the RE1-silencing transcription factor (REST), occupySPINK1promoter and functions as a direct transcriptional repressor ofSPINK1, thus blocking AR signaling via ADT relieves its repression, leading to SPINK1 upregulation. In agreement, an inverse association between SPINK1 levels and AR expression was observed across multiple PCa cohorts, and in neuroendocrine differentiated cells. While, lineage reprogramming factor SOX2 in turn binds toSPINK1promoter leading to its transactivation in androgen-deprived conditions with concomitant increase in neuroendocrine markers. Additionally, we also confirm the role ofSPINK1in epithelial-mesenchymal transition, drug resistance, stemness and cellular plasticity. Moreover, we show that Casein Kinase 1 inhibitor stabilizes the REST levels, which in cooperation with AR, conjures transcriptional repression ofSPINK1expression, and impedes SPINK1-mediated oncogenesis. Collectively, our findings provide a plausible explanation to the paradoxical clinical outcomes of ADT, possibly due to increased SPINK1 levels. This study highlights the need to take a well-informed decision prior to ADT and develop alternative therapeutic strategies for castrate-resistant PCa patients.

Introduction/Objective Renal mass biopsy is known to have a low but unavoidable diagnostic error rate. However, the occurrence of multiple adjacent masses mimicking one mass clinically has been minimally studied. Methods We report a series of four patients who were radiologically presumed to have a single renal mass and treated with partial nephrectomy, yet who were found to have multiple demarcated renal cell carcinoma histologies at pathologic evaluation. Results All were men aged 63–70 years. Grossly, tumors were red brown with scant, bright yellow foci in one of them. Dominant tumors followed by smaller tumors were: patient 1 - clear cell renal cell carcinoma (5.0 cm), clear cell papillary renal cell carcinoma (0.5 cm), and papillary adenoma (0.6 cm); patient 2 - clear cell renal cell carcinoma (1.5 cm) and clear cell papillary renal cell carcinoma (0.5 cm); patient 3 - papillary renal cell carcinoma (5.0 cm) and eosinophilic variant of chromophobe renal cell carcinoma (1.0 cm); patient 4 - chromophobe renal cell carcinoma (4.0 cm) and clear cell papillary renal cell carcinoma (0.6 cm). Immunohistochemical studies for cytokeratin 7, carbonic anhydrase IX, high molecular weight cytokeratin, CD10, and alpha-methyl acyl-CoA racemase (AMACR) confirmed the separate components in all. Conclusion This series adds to the spectrum of causes that may contribute to discordant results of renal mass biopsy and resection specimens. Secondary smaller tumors appear to be predominantly nonaggressive histologies, enriched for clear cell papillary renal cell carcinoma. Pathologists and urologists should be aware of this occurrence when considering the role of renal mass biopsy and interpreting the results.

Prostate cancer is a heterogeneous disease with unique molecular aberrations present in patient sub-groups. Distinct prostate cancer molecular changes have been shown to associate with specific clinical outcomes, suggesting the potential of molecular markers as diagnostic and prognostic biomarkers for prostate cancer. Recurrent ETS family gene fusions, BRAF and SPINK1 overexpression account for about 50-60% of the prostate cancer cases. Genetic aberrations in the remaining 40-50% of the cases is not known. Our attempt to identify new molecular markers in prostate cancer led to the identification of NAALADL2 gene shown to be associated with aggressive prostate cancer. In this study, we carried out a comprehensive analysis of genomic changes of NAALADL2 in prostate and other solid cancers by analyzing copy number changes and gene expression using TCGA next generation RNA sequencing data. We observed recurrent amplification, rearrangement, deletion, mutations and over-expression of NAALADL2 in prostate cancer cases. Notably, we observed mutually exclusive aberrations in NAALADL2 when compared to other cases with known prostate cancer aberrations including ETS gene fusions, indicating NAALADL2 as a distinct molecular sub-set of prostate cancer. Independent validation by fluorescent in situ hybridization (FISH) analysis using break apart probe for NAALADL2 on 874 prostate cancer revealed recurrent amplification and rearrangements in about 8% (71/874) [PN1] of the cases with higher prevalence in Caucasian American than African American cases. Based on these results, we explored prostate cancer TGCA gene fusion database and identified additional cases with gene fusions involving NAALADL2. We selected one of the gene fusions identified in the TCGA database involving NAALADL2-PIK3CA and conducted in vitro functional characterization studies and showed its oncogenic properties. Gene expression microarray analysis of RWPE1 cells transfected with NAALADL2-PIK3CA showed dysregulation of genes involved in cancer related pathways, further suggesting a role for NAALADL2-PIK3CA in prostate cancer development. Based on these studies, we explored the incidence of NAALADL2 gene fusion in other solid cancers including lung squamous cell cancer (LUSC), ovarian cancer, head and neck cancer, cervical cancer and breast cancer shown to have recurrent gene fusions identified in the TCGA gene fusion database. Notably, recurrent rearrangements and amplification are seen in a large subset (45%) of LUSC patients, but not in lung adenocarcinoma, suggesting that NAALADL2 could be developed as a novel biomarker in LUSC. Further validation studies using FISH in our independent cohort of LUSC and breast cancer patients including 79 patients from Ghana confirmed recurrent rearrangements and amplification in a subset of cases. In conclusion, similar to ERG, BRAF and FGFR genes, we show recurrent gene fusions of NAALADL2 across multiple solid cancer with potential applications as a pan cancer molecular marker for cancer diagnosis and a potential target for drug development. Citation Format: Pavithra D. Arachchige, Shannon Carskadon, James Hu, Justin Fernando, Darshan S. Chandrashekar, Nilesh S. Gupta, Sean R. Williamson, Dhananjay A. Chitale, Craig G. Rogers, James O. Peabody, Mani Menon, Tarek A. Bismar, Evelyn Jiagge, Sooryanarayana Varambally, Nallasivam Palanisamy. Recurrent rearrangements of NAALADL2 in prostate, breast, cervical, head and neck and lung squamous cell carcinoma [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2012.

Prostate cancer (PCa) is a heterogeneous disease and the diverse clinical outcomes may be associated with hitherto unidentified tumor molecular heterogeneity. In the era of precision medicine, new approaches to identify distinct molecular subsets of tumors may lead to the development of targeted treatment options. Given the disparity in the disease progression between African American (AA) and Caucasian American (CA) patients, understanding the existence of distinct molecular subtypes between the two racial groups may facilitate effective cancer management. Therefore, we carried out a comprehensive molecular analysis using prostate cancer-specific molecular markers, including ERG, ETV1, ETV4, ETV4, ETV5 and SPINK1, to study tumor molecular heterogeneity in a large cohort of AA and CA PCa patients. A total of 1,117 PCa cases comprising 575 (52%) CA and 453 (41%) AA patients were included in this study. Dual IHC for ERG/SPINK1 and RNA ISH for ETV1, ETV4 and ETV5 were carried out on whole mount prostatectomy specimens. Incidence of markers in each tumor foci, difference between the two racial groups, and the association of the markers with the clinical and pathologic findings in each racial group were analyzed. Independent clonal origin of tumor foci in patients with multifocal disease were observed with the presence of dual and triple marker positivity in dominant and/or secondary tumor foci. ERG was more frequently overexpressed among CA patients (P=0.0000) while SPINK1 was more prevalent among AA patients (P=0.0000). The incidence of dual marker positive cases for ERG+/SPINK1+ and SPINK1+/ETV1+ were more prevalent among AA patients than CA patients (P=0.0124 and P=0.0417, respectively). In both CA and AA patients, ERG overexpression is associated with young men age lower than 50 and a positive perineural invasion,(CA; P=0.0037 and P=0.0199, respectively; AA; P= 0.0338 and P=0.0309, respectively). Among CA patients, ERG overexpression also associated with a lower Gleason grade group (group 1 and 2, P=0.0483). SPINK1 overexpression associated with grade group lower than 5 and a negative family history among AA patients (P=0.0003 and P=0.0063). In CA patients, SPINK1 overexpression associated with grade group higher than 1, pT3 stage and tumor volume larger than 10% (P= 0.0036, P=0.0426 and P=0.0377, respectively). ETV1 overexpression is associated with positive family history (P=0.0043) and ETV4 overexpression associated with a tumor volume of 1-10% (P=0.0385) in CA patients. In AA patients, ETV4 expression associated with an age higher than 70 (P=0.0212). ERG/SPINK1 overexpression associated with grade group 2, tumor volume of 10-20%, and an age lower than 70 among CA patients (P=0.0013, P=0.0316, and P=0.0191, respectively). AA patients, on the other hand, showed an association between ERG/SPINK1 and age group lower than 40 (P=0.0092). We will discuss the details on the identification of new molecular subsets of PCa with clonal molecular heterogeneity in racial disparity perspective. Citation Format: Shannon Carskadon, Mireya Diaz-Insua, Nilesh Gupta, Sean Williamson, Craig Rogers, James Peabody, Mani Menon, Nallasivam Palanisamy. Comprehensive molecular mapping of prostate cancer- Approaching health disparities in molecular tumor heterogeneity perspective [abstract]. In: Proceedings of the Eleventh AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2018 Nov 2-5; New Orleans, LA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl):Abstract nr A113.

PurposeSerine Peptidase Inhibitor, Kazal type-1 (SPINK1) overexpression defines the second most recurrent and aggressive prostate cancer (PCa) subtype. However, the underlying molecular mechanism and pathobiology of SPINK1 in PCa remains largely unknown.Experimental DesignMicroRNA-prediction tools were employed to examine theSPINK1-3’UTR for miRNAs binding. Luciferase reporter assays were performed to confirm theSPINK1-3’UTR binding of shortlisted miR-338-5p/miR-421. Further, miR-338-5p/-421 overexpressing cancer cells (SPINK1-positive) were evaluated for oncogenic properties using cell-based functional assays and mice xenograft model. Global gene expression profiling was performed to unravel the biological pathways altered by miR-338-5p/-421. Immunohistochemistry and RNAin-situhybridization was carried-out on PCa patients’ tissue microarray for SPINK1 andEZH2expression respectively. Chromatin immunoprecipitation assay was performed to examine EZH2 occupancy on the miR-338-5p/-421 regulatory regions. Bisulfite sequencing and methylated DNA-immunoprecipitation was performed on PCa cell lines and patients’ specimens.ResultsWe established a critical role of miRNA-338-5p/-421 in post-transcriptional regulation ofSPINK1. Ectopic expression of miRNA-338-5p/-421 in SPINK1-positive PCa cells abrogate oncogenic properties including cell-cycle progression, stemness and drug resistance, and show reduced tumor burden and distant metastases in mice model. Importantly, we show SPINK1-positive PCa patients exhibit increased EZH2 expression, suggesting its role in miRNA-338-5p/-421 epigenetic silencing. Furthermore, presence of CpG dinucleotide DNA methylation marks on the regulatory regions of miR-338-5p/-421 in SPINK1-positive PCa cells and patients’ specimens confirms epigenetic silencing.ConclusionOur findings revealed that miRNA-338-5p/-421 are epigenetically silenced in SPINK1-positive PCa, while restoring the expression of these miRNAs using epigenetic drugs or synthetic mimics could abrogate SPINK1-mediated oncogenesis.TRANSLATIONAL IMPACTWe establish a regulatory model involving the functional interplay between SPINK1, miRNA-338-5p/miRNA-421 and EZH2, thereby, revealing hitherto unknown mechanism of SPINK1 up-regulation in SPINK1-positive subtype. Our findings provide a strong rationale for the development of potential therapeutic strategies for SPINK1-positive malignancies. We demonstrate that restoring miRNA-338-5p/miRNA-421 expression using epigenetic drugs including DNMTs inhibitors in combination with HDACs or HKMTs inhibitors or miRNA synthetic mimics in SPINK1-positive prostate cancer abrogate SPINK1-mediated oncogenicity. The major findings of this study will not only advance the prostate cancer field, but will also be valuable for treatment and disease management of other SPINK1-positive malignancies.

Aims Pathological staging of renal cell carcinoma (RCC) can be challenging compared to other cancer types, as invasion often manifests as finger-like protrusions into vascular spaces or renal sinus tissue. Although prior studies have shown larger tumour size to be correlated highly with renal sinus invasion, prospective data on evaluating pathological stage are limited. We evaluated a large series reported by one urological pathologist. Methods and results Three hundred consecutive specimens were reviewed. Tumours larger than 5 cm were routinely sampled extensively or grossly re-reviewed when no extrarenal extension was identified on initial examination. Apparent multifocal disease was assessed critically for intravascular spread. Retrograde venous invasion was reported in 15 of 300 (5%) cases, 13 of 15 of which were clear cell RCC. Of a total of 163 specimens with clear cell histology, only five of 34 (15%) tumours 7 cm or larger were reported as pT2, all of which had an explanatory comment indicating the absence of definitive extrarenal spread. In contrast, 15 of 20 (75%) pT2 tumours were non-clear cell histology (papillary, chromophobe and translocation-associated). Comparing pT3a or higher tumours, the median tumour size in cases with retrograde venous invasion was 8.0 cm, compared to 6.2 cm in cases without retrograde venous invasion (P = 0.005). Conclusions Our findings support that retrograde venous invasion should be considered carefully before diagnosing multifocal clear cell RCC, which is rare in the sporadic setting. In the absence of vascular invasion, multifocal clear cell papillary RCC can be a mimic. pT2 occurs more frequently with non-clear cell histology (particularly papillary or chromophobe RCC).

Cadmium is a known carcinogen that has been implicated in prostate cancer, but how it affects prostate carcinogenesis in humans remains unclear. Evidence from basic science suggests that cadmium can bind to the androgen receptor causing endocrine disruption. The androgen receptor is required for normal prostate development and is the key driver of prostate cancer progression. In this study, we examined the association between cadmium content and androgen receptor protein expression in prostate cancer tissue of African American (N = 22) and European American (N = 30) men. Although neither overall tumor cadmium content (log transformed) nor androgen receptor protein expression level differed by race, we observed a race-cadmium interaction with regard to androgen receptor expression ( P = 0.003) even after accounting for age at prostatectomy, smoking history, and Gleason score. African American men had a significant positive correlation between tumor tissue cadmium content and androgen receptor expression (Pearson correlation = 0.52, P = 0.013), while European Americans showed a non-significant negative correlation between the two (Pearson correlation = −0.19, P = 0.31). These results were unchanged after further accounting for tissue zinc content or dietary zinc or selenium intake. African American cases with high-cadmium content (>median) in tumor tissue had more than double the androgen receptor expression (0.021 vs. 0.008, P = 0.014) of African American men with low-cadmium level. No difference in androgen receptor expression was observed in European Americans by cadmium level (high 0.015 vs. low 0.011, P = 0.30). Larger studies are needed to confirm these results and if upheld, determine the biologic mechanism by which cadmium increases androgen receptor protein expression in a race-dependent manner. Our results suggest that cadmium may play a role in race disparities observed in prostate cancer.

Epidemiologic studies, primarily done in white men, suggest that a history of clinically-diagnosed prostatitis increases prostate cancer risk, but that histological prostate inflammation decreases risk. The relationship between a clinical history of prostatitis and histologic inflammation in terms of how these two manifestations of prostatic inflammation jointly contribute to prostate cancer risk and whether racial differences exist in this relationship is uncertain.Using a nested design within a cohort of men with benign prostate tissue specimens, we analyzed the data on both clinically-diagnosed prostatitis (NIH categories I-III) and histological inflammation in 574 prostate cancer case-control pairs (345 white, 229 African American).Clinical prostatitis was not associated with increased prostate cancer risk in the full sample, but showed a suggestive inverse association with prostate cancer in African Americans (odds ratio (OR)=0.47; 95% confidence interval (CI)=0.27-0.81). In whites, clinical prostatitis increased risk by 40%, but was only associated with a significant increased prostate cancer risk in the absence of evidence of histological inflammation (OR=3.56; 95% CI=1.15-10.99). Moreover, PSA velocity (P=0.008) and frequency of PSA testing (P=0.003) were significant modifiers of risk. Clinical prostatitis increased risk of prostate cancer almost three-fold (OR=2.97; 95% CI=1.40-6.30) in white men with low PSA velocity and about twofold in white men with more frequent PSA testing (OR=1.91; 95% CI=1.09-3.35).In our cohort of men with benign prostate specimens, race, and histological inflammation were important cofactors in the relationship between clinical prostatitis and prostate cancer. Clinical prostatitis was associated with a slightly decreased risk for prostate cancer in African American men. In white men, the relationship between clinical prostatitis and prostate cancer risk was modified by histological prostatic inflammation, PSA velocity, and frequency of PSA testing-suggesting a complex interplay between these indications of prostatic inflammation and prostate cancer detection.

Objectives: Prostate cancer screening algorithms and preoperative nomograms do not include patients’ body mass index (BMI). We evaluated outcomes at radical prostatectomy (RP) adjusted to BMI. Methods: Serum prostate-specific antigen (PSA) levels, PSA mass, PSA density (PSAD), and RP findings were analyzed with respect to BMI in 4,926 men who underwent RP between 2005 and 2014. Results: In total, 1,001 (20.3%) men were normal weight, 2,547 (51.7%) were overweight, and 1,378 (28%) were obese. Median PSA levels (ng/mL) were normal weight, 5.0; overweight, 5.1; and obese, 5.2 (P = .094). Median PSA mass increased with increasing BMI: 15.9 vs 17.4 vs 19.4 μg (P < .001). Median PSAD was not significantly different: 0.11 vs 0.11 vs 0.11 ng/mL/g (P = .084). Median prostate weight increased with increasing BMI: 44 vs 45 vs 49 g (P < .001). Median prostatectomy tumor volume increased with increasing BMI: 3.9 vs 4.7 vs 5.9 cm3 (P < .001). Overweight and obese patients had a higher Gleason score and more locally advanced cancer (P < .001). Frequency of positive surgical margins increased with higher BMIs (P < .001). Frequency of lymph node metastasis did not differ significantly (P = .088). Conclusions: While BMI correlates with tumor volume, Gleason score, and extent of disease at RP, there is no routinely measured clinical parameter reflecting this. Only PSA mass highlights this correlation. Thus, BMI and potentially PSA mass should be taken into account in predictive algorithms pertaining to prostate cancer and its surgical treatment.

Pseudocapsule in renal cell carcinoma (RCC) has been described but little is known about its prevalence and extent. Pseudocapsule was analyzed in 105 RCCs (44 clear cell, 44 chromophobe, 17 papillary). Pseudocapsule was graded as follows: grade 1, thickness comparable to adjacent muscular arteries; grade 2, thickness more than twice the diameter of adjacent muscular arteries; grade 3, grade 2 findings with vasculopathy. Tumor size, tumor regression, and International Society of Urologic Pathology (ISUP) nucleolar grade were recorded. Cases with grade 3 pseudocapsule were stained with elastic silver stain, Alcian blue, smooth muscle actin, and CD31. More clear cell RCCs had pseudocapsule (89%, 39/44) than chromophobe (30%, 13/44) and papillary (35%, 6/17). Average tumor size with pseudocapsule was 3.9 cm; average tumor size without pseudocapsule was 3.8 cm ( P = .77). Grade 2 pseudocapsule was common in clear cell RCC (56%, 22/39). Chromophobe and papillary RCC had grade 1 pseudocapsule in 77% (10/13) and 83% (5/6) of cases. Grade 3 pseudocapsule was only seen in clear cell RCC (10%, 4/39). No correlation was noted between degenerative tumor changes, tumor size, ISUP nucleolar grade, and presence and grade of pseudocapsule. Smooth muscle actin and CD31 showed abundant smooth muscle component and rich vasculature within the pseudocapsule. Arterial elastic membrane disruption and/or fibrointimal mucin deposits were present in grade 3 pseudocapsule. Thus, pseudocapsule is rather characteristic and more prominent in clear cell, less frequent in chromophobe, and rare in papillary RCC. Its presence may be evaluated radiologically or in biopsy specimens with scant tumor fragments.

Rare renal epithelial neoplasms have been recognized to have an angioleiomyoma or leiomyoma-like proliferation of stromal smooth muscle; however, the nature of these tumors and their relationships to other renal cell carcinomas are poorly understood. We analyzed 23 such tumors for their clinicopathological, immunohistochemical, and cytogenetic features using fluorescence in situ hybridization. Twelve showed a homogeneous combination of features and were reclassified as renal cell carcinoma with angioleiomyoma-like stroma. These were composed of neoplastic glandular structures lined by cells with mixed clear, pale, and eosinophilic cytoplasm forming occasional papillary tufts. The stroma resembled smooth muscle and often extended away from the epithelial component, entrapping perinephric fat or non-neoplastic renal elements. Immunohistochemistry showed the epithelium to have reactivity for: carbonic anhydrase IX, CD10, vimentin, cytokeratin 7, cytokeratin 34βE12, and PAX8 but not α-methylacyl-coA-racemase. The stroma labeled for smooth muscle (smooth muscle actin 3+, desmin 1+, caldesmon 3+) but not epithelial antigens. Neither component showed substantial reactivity for HMB45, melan-A, cathepsin K, or TFE3 protein. An interrupted, conspicuous layer of CD34-positive endothelial cells rimmed the epithelium, imparting a two-cell layer pattern resembling myoepithelial or basal cells. Chromosome 3p deletion and trisomy 7 and 17 were uniformly absent. Follow-up was available for three patients, none of whom experienced malignant behavior. Eleven tumors were excluded from this category and considered to be clear cell renal cell carcinoma with a reactive proliferation of smooth muscle (n=4) or tangential sectioning of the pseudocapsule (n=2), renal cell carcinoma unclassified (n=4), or clear cell papillary renal cell carcinoma (n=1). In summary, renal cell carcinoma with angioleiomyoma-like stroma is a distinct neoplasm with characteristic morphological, immunohistochemical, and molecular features, unrelated to clear cell renal cell carcinoma. The immunoprofile overlaps partly with that of clear cell papillary renal cell carcinoma, though morphology and reactivity for CD10 are points of contrast.

Recently, rare renal cell carcinomas (RCCs) have been reported to closely mimic hemangioma; however, these have been largely recognizable as clear cell RCC. Conversely, true hemangiomas of the kidney are also increasingly recognized. We report a 62-year-old woman who underwent partial nephrectomy for a hemangioma-like RCC without appreciable clear cell morphology. Immunohistochemistry revealed luminal structures that stained positively for cytokeratin, cytokeratin 7, carbonic anhydrase IX, PAX8, and high-molecular-weight keratin, admixed with a CD34-positive, CD31-positive, and ERG-positive complex network of vessels. Staining was minimal for α-methyl-acyl-coA-racemase and EMA, and absent for GATA3, HMB45, melan-A, and cathepsin K. Fluorescence in situ hybridization revealed no TFE3 or TFEB rearrangement, 3p deletion, or trisomy 7 or 17. This case adds to the spectrum of hemangioma-like RCC with differing morphology and immunophenotype. Further study will determine whether this represents a distinct entity or an unusual pattern of degenerative changes in an existing entity.

Renal cell carcinoma (RCC) with angioleiomyoma-like stroma appears to be molecularly distinct from clear cell RCC; however, its relationship to clear cell papillary RCC remains debated. Recent studies have found that similar tumors sometimes occur in patients with tuberous sclerosis complex (TSC), of which 1 study found unexpectedly negative succinate dehydrogenase B (SDHB) immunostaining. We evaluated immunohistochemistry for SDHB in 12 apparently sporadic RCCs with angioleiomyoma-like stroma and correlated with clinical information for stigmata of TSC. Tumors were compared with a group of 16 clear cell papillary RCCs and 6 unclassified tumors with prominent stroma. With the exception of 1 unclassified tumor, all exhibited at least focal cytoplasmic staining for SDHB protein, often requiring high magnification and better appreciated with increased antibody concentration. Detailed history information was available for 9 of 11 patients with smooth muscle-rich tumors, revealing no stigmata of undiagnosed TSC. Electron microscopy performed on 1 of these tumors revealed mitochondria to be very sparse, potentially accounting for the weak immunohistochemical labeling for SDHB protein. Weak SDHB immunostaining may represent another shared feature of RCC with angioleiomyoma-like stroma and clear cell papillary RCC, likely due to sparse mitochondria, strengthening the possible relationship of these entities. Although smooth muscle-rich tumors have been recently reported in patients with TSC, absence of staining in tumors with this pattern may not be specific for TSC. In tumors with pale or clear cytoplasm, immunohistochemical staining for SDHB should be interpreted with caution as evidence of abnormality in the SDH pathway.