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Background Re-irradiation for recurrent gliomas is a controversial treatment option with no clear standard dose or concurrent systemic therapy. Methods This series represents a single-institution retrospective review of patients treated with re-irradiation for recurrent high-grade glioma. After 2012, patients were commonly offered concurrent bevacizumab as a cytoprotective agent against radiation necrosis. Kaplan-Meier method was used to estimate overall survival and progression-free survival. Cox proportional hazards regression was used to identify factors associated with overall survival and progression-free survival. Results Between 2001 and 2021, 52 patients underwent re-irradiation for a diagnosis of recurrent high-grade glioma. 36 patients (69.2%) had a histologic diagnosis of glioblastoma at the time of re-irradiation. The median BED10 (biological equivalent dose 10 Gy) of re-irradiation was 53.1 Gy. Twenty-one patients (40.4%) received concurrent bevacizumab with re-irradiation. Median survival for the entire cohort and for glioblastoma at the time of recurrence patients was 6.7 months and 6.0 months, respectively. For patients with glioblastoma at the time of recurrence, completing re-irradiation (HR 0.03, P < .001), use of concurrent bevacizumab (HR 0.3, P = .009), and the BED10 (HR 0.9, P = .005) were predictive of overall survival. Nine patients developed grade 3-5 toxicity; of these, 2 received concurrent bevacizumab and 7 did not (P = .15). Conclusion High dose re-irradiation with concurrent bevacizumab is feasible in patients with recurrent gliomas. Concurrent bevacizumab and increasing radiation dose may improve survival in patients with recurrent glioblastoma.

Neuromuscular ultrasound (NMUS) is a valuable tool in establishing a diagnosis of carpal tunnel syndrome (CTS), and can be particularly helpful in patients with clinical CTS but normal nerve conduction studies (NCS). This case involves the uncommon presentation of enlarged median nerves on NMUS with normal NCS in a breast cancer patient who developed chemotherapy induced peripheral neuropathy (CIPN) and CTS following taxane treatment. This case demonstrates that CTS should not be excluded based on electrodiagnostic studies alone, and comorbid CTS should be considered in patients receiving neurotoxic chemotherapy, even in the setting of normal NCS.

Purpose: RTOG 9802 demonstrated improved survival with the use of chemoradiotherapy (CRT) over radiotherapy (RT) alone for WHO grade II gliomas (LGG) using PCV chemotherapy. We analyzed our retrospective dataset of predominantly temozolomide (TMZ)-based CRT in patients with LGG who would have been eligible for RTOG 9802. Methods: We identified 67 patients (n= 38 astrocytoma (AC), 20 oligodendroglioma (OD), and 9 mixed (OA)) treated with upfront RT from 2000-2017. The CRT cohort (n=40) primarily consisted of TMZ (n=36) administered concurrently with RT. The median RT dose was 54 Gy (range 35-54 Gy). Kaplan- Meier analysis was used to assess overall survival (OS) and progression-free survival (PFS). Results: 5-year PFS was 64% vs. 44% for patients receiving CRT vs. RT alone (log-rank p=0.009). 5-year PFS for AC patients receiving CRT vs. RT alone was 57% vs. 21%, respectively (log-rank p=0.002) while 5-year PFS for OD/OA patients receiving CRT vs. RT alone was 79% vs. 72% (p=0.21). 5-year OS was 76% vs. 69% (p=0.10 ) for CRT vs. RT alone. Cox Proportional Hazards analysis revealed that patients with AC (HR=4.89, 95% CI (1.95, 12.3), p=0.0007), neurological deficits (HR=2.34, (1.12, 4.88), p=0.023), and tumors>6 cm (HR=2.69, (1.10, 6.58), p=0.03) had decreased OS. Cox analysis showed that use of upfront CRT (HR=0.40 , (0.20, 0.79), p=0.0086) was the only factor that improved PFS. Conclusion: The use of upfront, predominantly TMZ-based, CRT has a PFS benefit over RT alone in patients with LGG.

Background Laser interstitial thermal therapy (LITT) in the setting of post-SRS radiation necrosis (RN) for patients with brain metastases has growing evidence for efficacy. However, questions remain regarding hospitalization, local control, symptom control, and concurrent use of therapies. Methods Demographics, intraprocedural data, safety, Karnofsky performance status (KPS), and survival data were prospectively collected and then analyzed on patients who consented between 2016–2020 and who were undergoing LITT for biopsy-proven RN at one of 14 US centers. Data were monitored for accuracy. Statistical analysis included individual variable summaries, multivariable Fine and Gray analysis, and Kaplan–Meier estimated survival. Results Ninety patients met the inclusion criteria. Four patients underwent 2 ablations on the same day. Median hospitalization time was 32.5 hours. The median time to corticosteroid cessation after LITT was 13.0 days (0.0, 1229.0) and cumulative incidence of lesional progression was 19% at 1 year. Median post-procedure overall survival was 2.55 years [1.66, infinity] and 77.1% at one year as estimated by KaplanMeier. Median KPS remained at 80 through 2-year follow-up. Seizure prevalence was 12% within 1-month post-LITT and 7.9% at 3 months; down from 34.4% within 60-day prior to procedure. Conclusions LITT for RN was not only again found to be safe with low patient morbidity but was also a highly effective treatment for RN for both local control and symptom management (including seizures). In addition to averting expected neurological death, LITT facilitates ongoing systemic therapy (in particular immunotherapy) by enabling the rapid cessation of steroids, thereby facilitating maximal possible survival for these patients.

Purpose To provide guidance to clinicians regarding therapy for diffuse astrocytic and oligodendroglial tumors in adults. Methods ASCO and the Society for Neuro-Oncology convened an Expert Panel and conducted a systematic review of the literature. Results Fifty-nine randomized trials focusing on therapeutic management were identified. Recommendations Adults with newly diagnosed oligodendroglioma, isocitrate dehydrogenase (IDH)–mutant, 1p19q codeleted CNS WHO grade 2 and 3 should be offered radiation therapy (RT) and procarbazine, lomustine, and vincristine (PCV). Temozolomide (TMZ) is a reasonable alternative for patients who may not tolerate PCV, but no high-level evidence supports upfront TMZ in this setting. People with newly diagnosed astrocytoma, IDH-mutant, 1p19q non-codeleted CNS WHO grade 2 should be offered RT with adjuvant chemotherapy (TMZ or PCV). People with astrocytoma, IDH-mutant, 1p19q non-codeleted CNS WHO grade 3 should be offered RT and adjuvant TMZ. People with astrocytoma, IDH-mutant, CNS WHO grade 4 may follow recommendations for either astrocytoma, IDH-mutant, 1p19q non-codeleted CNS WHO grade 3 or glioblastoma, IDH-wildtype, CNS WHO grade 4. Concurrent TMZ and RT should be offered to patients with newly diagnosed glioblastoma, IDH-wildtype, CNS WHO grade 4 followed by 6 months of adjuvant TMZ. Alternating electric field therapy, approved by the US Food and Drug Administration, should be considered for these patients. Bevacizumab is not recommended. In situations in which the benefits of 6-week RT plus TMZ may not outweigh the harms, hypofractionated RT plus TMZ is reasonable. In patients age ≥ 60 to ≥ 70 years, with poor performance status or for whom toxicity or prognosis are concerns, best supportive care alone, RT alone (for MGMTpromoter unmethylated tumors), or TMZ alone (for MGMT promoter methylated tumors) are reasonable treatment options. Additional information is available at www.asco.org/neurooncology-guidelines.

Treatment options for glioblastoma remain limited, particularly for those who are not eligible for traditional resection, whether due to lesion location or inability to tolerate open craniotomy. Maximal-safe resection followed by radiation with concurrent and adjuvant temozolomide offers the best outcomes for patients. Unfortunately, not all tumors are amenable to conventional surgical resection at the time of diagnosis with only about 1/3 of patients able to receive a gross-total resection and 15-25% of patients receiving biopsy only, thus reducing their projected overall survival to 9 months. Laser interstitial thermal therapy (LITT) is a minimally invasive, cytoreductive tool, that has demonstrated safety as a surgical approach to treat primary brain tumors. METHODS Data from LAANTERN prospective multicenter registry (NCT02392078) was analyzed to determine clinical outcomes for patients with new and recurrent IDH wild-type glioblastoma (N=89). Demographics, intraprocedural data, adverse events, KPS, health-economics, and survival data were prospectively collected then analyzed separately for newly diagnosed GBM (N=29) and recurrent GBM (N=60). RESULTS Median overall-survival was 9.73 months (95% CI: 5.16, 15.91) for newly diagnosed patients and median post-procedure survival was 8.97 (6.94, 12.36) months for recurrent patients. Median overall-survival for newly diagnosed patients receiving post-LITT chemoradiotherapy was 16.14 months (6.11, not reached). The median length of hospital stay was 50 hours and 80% of patients were discharged to home. CONCLUSIONS LITT offers an effective cytoreductive approach for patients with newly diagnosed and recurrent IDH wild-type glioblastoma. Importantly, its use in newly diagnosed patients who receive post-LITT chemoradiotherapy leads to a median OS similar to that of patients treated with conventional surgical resection. LITT remains an important alternative for patients with inoperable tumors or those not amenable to resection. Enrollment in LAANTERN is ongoing and these cohorts will be revisited as data continues to mature. Benefits beyond cytoreduction are also being actively explored.

Wrist drop is a common presentation in neurology. To localize the lesion, clinicians can focus on testing finger extension, elbow flexion with semipronated forearm, and elbow extension among other muscle groups and identifying dermatomes of numbness. Once the lesion is localized, electrophysiology or imaging can guide to an underlying etiology. Here, we describe a case that illustrates the importance of using a stepwise approach to diagnose the etiology of wrist drop in a patient with a cancer history. A 65-year-old woman with diffuse large B-cell lymphoma in remission presented with new onset wrist drop, severe pain, numbness, and tingling concerning for peripheral nerve injury. Imaging findings from PET, venous ultrasound, nerve conduction velocity study, and MRI were conflicting favoring deep venous thrombosis, cancer recurrence, or peripheral nerve sheath tumor. A biopsy was ultimately required to confirm the diagnosis.

BACKGROUND KRT232 is an orally bioavailable, selective small molecule inhibitor of MDM2 that blocks the protein-protein interaction between MDM2 and p53. We performed a surgical window of opportunity trial of KRT232 in patients with recurrent GBM. METHODS The primary endpoint was to determine the tumor tissue concentration of KRT232. Prior to surgery, patients received KRT232 at either 120mg (n = 10, minimal dose that is consistently associated with alterations in serum MIC-1) or 240mg (n = 10; recommended phase 2 dose as monotherapy) for two days prior to surgical resection. Surgery was performed 3-6 hours following the last administration of KRT232. Tissue was analyzed for KRT232 concentration by LC/MS and for correlative studies. Participants with TP53 wild-type tumors were eligible to continue KRT232 following recovery from surgery at the RP2D of 240mg QD x 7 days q3weeks. RESULTS Twenty-one patients were enrolled from July 2018 to April 2020. One patient was deemed ineligible after surgery due to non-GBM tumor. Study met the prespecified criteria of target intra-tumor drug concentration of ≥ 25nM in contrast enhancing tissue in more than 50% of the patients in the 120mg cohort (67.1 ± 42.7nM in 8/10 patients) and 240mg (328.7 ± 468.1nM in 10/10 patients) cohort. Serum MIC-1 fold-changes from baseline (FCB) approximately 24 hours after a single dose of KRT232 were higher in the 240mg cohort (9.1 ± 4.1-FCB) than the 120mg cohort (3.6 ± 2.0-FCB). CDKN1A (p21), a downstream marker of p53, was significantly upregulated in analyzed participants whose GBM was TP53 wildtype, but not in TP53 mutant GBM or control samples (GBM treated with standard of care). CONCLUSION KRT232 at both 120mg and 240mg achieves adequate tumor tissue penetration and affects downstream pathways in TP53 wildtype GBM. The study has moved to Alliance to complete a phase 1 study of radiation + KRT232 in patients with newly diagnosed MGMT unmethylated GBM.

BACKGROUND Although < 5% of high-grade gliomas (HGG) are BRAF-V600E mutated, these tumors are being identified more frequently as genetic testing increases in gliomas. Given the treatment-refractory nature HGG, RAF-targeted therapy is of special interest. The combination of encorafenib (BRAF inhibitor) with binimetinib (MEK inhibitor) was evaluated in adults with recurrent BRAFV600-mutated HGG. METHODS In this phase 2, open-label, Adult Brain Tumor Consortium trial(NCT03973918) encorafenib (450mg daily) and binimetinib (45mg twice daily) were administered continuously until disease progression, unacceptable toxicity, or death. Eligible patients had a histologically-confirmed HGG with BRAF-V600E mutation identified by PCR or next generation sequencing, and had progressed after radiation and any number of prior medical therapies. The primary endpoint was radiographic response rate by RANO criteria. Plasma was collected at baseline, on-study, and at progression for correlatives. RESULTS Five patients enrolled between January 2020 and November 2021. All patients had at least one prior recurrence (range 1-4) and received radiation one or more times. Median age was 27 years(range 22-77). Histopathologic diagnosis was glioblastoma(n = 2), anaplastic PXA(aPXA; n = 2), and anaplastic ganglioglioma(aGG; n = 1). Patients received treatment for 2-28months; currently 2/5 patients remain on treatment (8 and 30 months). Radiographic response rate was 60%(3/5): CR in two (glioblastoma, treated 10months; glioblastoma, 8months treatment ongoing), PR in one (aPXA, 28months treatment ongoing), SD in one (aGG, treated 3months), and PD in one (aPXA, treated 2months). Likely attributable adverse events (CTCAE grade ≥ 3) included cilioretinal artery occlusion (came off study) and asymptomatic elevated CPK. Analysis of paired plasma samples and correlation with response is ongoing. CONCLUSIONS Encorafenib and binimetinib demonstrate promising tumor responses in patients with recurrent BRAFV600E-mutated HGG with sustained responses in all GBM and 50% of aPXA in this small series, warranting careful consideration in this rare tumor subgroup. This Phase 2 study has closed due to enrollment issues

OBJECTIVE RTOG 9802 demonstrated improved survival using chemoradiotherapy (CRT) over radiotherapy (RT) alone for WHO Grade II gliomas (LGG) using PCV with RT. We analyze our retrospective dataset of predominantly temozolomide (TMZ)-based CRT in LGG patients who would have been eligible for RTOG 9802. METHODS Retrospective review of LGG patients (2000–2017) treated at a single institution (67 patients). Histologies included oligodendroglioma(OD), astrocytoma(AC) or astrocytoma (OA). Those who received upfront RT +/- chemotherapy were included. The CRT cohort (n=40) consisted primarily of TMZ (n=36) administered concurrently with RT. 27 patients received RT alone. RT for both cohorts consisted of a median dose of 54 Gy (range 50.4 - 54 Gy). 65/67 patients had “high risk” LGG as defined by RTOG 9802 criteria. Kaplan Meier analysis was used to assess overall survival (OS) and progression free survival (PFS). RESULTS 5-year PFS for patients receiving CRT was 64% vs. 44% in those receiving RT alone (log rank p=0.009). Difference in PFS due to chemotherapy was driven by AC histology (57% vs. 21% PFS at 5 years, log rank p=0.002) while OD/OA PFS was not statistically altered (79% vs. 72% PFS at 5 years, p=0.21). 5-year OS for patients receiving CRT was 76% vs. 69% in those receiving RT alone (p=0.11). Cox Proportional Hazards analysis showed that use of upfront CRT (HR=0.4, p=0.009) was the only factor that decreased the risk of earlier progression. CONCLUSION Use of upfront, predominantly TMZ-based CRT, has a PFS benefit over RT alone in a population of WHO grade II gliomas. This benefit appears to be driven by AC histology and also appears to extend beyond the “very high risk” cohort from RTOG 0424 to include the “high risk” group from RTOG 9802.

BACKGROUND The blood brain barrier (BBB) is a major obstacle to the delivery of chemotherapy to the CNS. Regadenoson is an FDA approved adenosine A2 agonist used for cardiac stress tests. In murine models, it transiently increases BBB permeability to a 70KD dextran. This multi-institutional, NIH funded, Adult Brain Tumor Consortium trial was designed to discover a dose of regadenoson that substantially increases vascular permeability in normal appearing white matter (NAWM) where drug delivery is particularly challenging. METHODS Adults ages 18-45 with supratentorial gliomas at low-risk for regadenoson complications were recruited (n = 7). One patient was treated at each of seven dose levels (from 0.05 to 1.4 mg) that are known to be safe in humans. The primary outcome measure is change in vascular permeability via dynamic contrast enhanced (DCE) perfusion MRI estimates of Ktrans. The primary outcome measure was a 10-fold higher Ktrans in NAWM than reported in literature (Ktrans > 0.04 min-1). Contrast-enhanced T1 subtraction map estimates of change in contrast enhancement and other measurements in normal brain and non-enhancing tumor were quantified. RESULTS Ktrans measures in NAWM averaged 1.13x10-3 ± 0.44x10-3 (SEM) min-1, lower than the target of 0.04 min-1. Normalized, contrast enhanced T1-weighted MR signal intensity in NAWM increased an average of 74.0 ± 22.4% min-1 (SEM) min-1, which was significantly higher than zero (P = 0.0163). Data available from this limited sample failed to meet the target goal in Ktrans increase or change in contrast enhancing signal intensity. CONCLUSION Administration of regadenoson at seven different doses did not significantly elevate Ktrans for gadolinium in NAWM. This data suggests that single doses of regadenoson are unlikely to substantially increase the delivery of therapeutic agents in non-enhancing brain tissue. This trial design is appropriate for further human testing of other regadenoson schedules and other novel approaches aimed at transiently modifying BBB permeability.

INTRODUCTION Immunotherapies targeting PD-1 in recurrent glioblastoma (rGBM) have shown limited activity. We hypothesize combining therapies targeting immunosuppressive pathways with cytotoxic and antiangiogenic therapies will improve survival. This nonrandomized, noncomparative Phase II study examines safety and efficacy of an anti-PD-1 monoclonal antibody (retifanlimab), hypofractionated radiotherapy (HFRT), and bevacizumab, with or without an IDO1 inhibitor (epacadostat), in patients with rGBM. METHODS This is an open-label Phase II study of two regimens. Regimen A examines retifanlimab (500mg IV Q4W) + bevacizumab (10mg/kg IV Q2W) + HFRT (3.5Gy/day x 10) in patients with IDH1/2-WT rGBM. Regimen B adds epacadostat. Key inclusions include dexamethasone ≤ 4 mg/day and reirradiation candidacy. The primary endpoint is overall survival (OS) probability at 9 months (OS-9). An increase of OS-9 from 38% (bevacizumab alone) to 60% was considered clinically relevant and required 24 efficacy evaluable patients. RESULTS Regimen A accrual is complete; interim results are as follows: 26 rGBM enrolled, with 24 evaluable [median age 64.2 years (42.1-81.8); 29% female; 29% MGMT promotor methylated; 33.3% with multi-focal disease; median KPS 90 (70-100); median baseline dexamethasone 0 mg (0-4) and ALC 1,000 cells/µl (300-3,700)]. Patients received a median of 6 cycles as of May 2022 (2-24). Median follow-up is 16.0 months. Interim median PFS is 7.0 months (95%CI: 4.5~11.1) and median OS is 12.2 months (95%CI 7.1~18.0). Regimen A met primary endpoint with OS-9 of 67% (95%CI: 44~82%). Overall response rate is currently 58% (95%CI: 36.94~77.2%). There were five possible immune-related grade 3+ toxicities to date (n = 1 each colitis, vomiting, and seizure; n = 2 diarrhea). Regimen B is enrolling. CONCLUSIONS Interim analysis suggests combination retifanlimab, HFRT, and bevacizumab in rGBM is generally well-tolerated, with encouraging OS and PFS at the time of submission. Correlative analysis is ongoing and will be presented at the meeting.

Background B-cell primary central nervous system (CNS) lymphoma (PCL) is diffuse large B-cell lymphoma (DLBCL) confined to the CNS. Less than 50% of patients with PCL achieve complete remission with current therapies. We describe the findings from comprehensive genomic profiling (CGP) of a cohort of 69 patients with PCL, 36 cases of secondary CNS lymphoma (SCL), and 969 cases of DLBCL to highlight their differences and characterize the PCL cohort. In addition, we highlight the differences in frequency of germinal center B-cell like (GCB) and non-GCB subtypes and molecular subtypes, particularly MCD and EZH subtypes, between PCL and DLBCL. Materials and Methods Sixty-nine cases of B-cell PCL, 36 cases of secondary CNS lymphoma (SCL), and 969 cases of DLBCL were evaluated by CGP of 405 genes via DNAseq and 265 genes via RNAseq for fusions (FoundationOne Heme). Tumor mutational burden (TMB) was calculated from 1.23 Mb of sequenced DNA. Results Genomic alterations with significant differences between PCL and DLBCL included MYD88, ETV6, PIM1, PRDM1, CXCR4, TP53, and CREBBP, while only MYD88 was significantly different between SCL and DLBCL. PCL cases were significantly enriched for the MCD molecular subtypes, which have an excellent response to BTKi. We report a patient with a durable complete response to BTKi consistent with their genomic profile. EBV status, CD274 amplification, and TMB status suggest that 38% of PCL patients may benefit from ICPI; however further study is warranted. Conclusion CGP of PCLs reveals biomarkers, genomic alterations, and molecular classifications predictive of BTKi efficacy and potential ICPI efficacy. Given the limitations of standard of care for PCL, CGP is critical to identify potential therapeutic approaches for patients in this rare form of lymphoma.

Background Experts in the field of medical education emphasized the need for curricula that improve students’ attitudes toward the underserved. However, some studies have shown that medical education tends to worsen these attitudes in students. We aimed at systematically reviewing the literature assessing the change in medical students’ attitudes toward the underserved and intention to work with the underserved throughout medical education, the sociodemographic and educational factors associated with favorable medical student attitudes toward and/or intention to work with the underserved and the effectiveness of educational interventions to improve medical student attitudes toward and/or intention to work with the underserved. Method We conducted a systematic review on MEDLINE, Scopus, and Web of Science databases. Three investigators independently conducted the electronic search. We assessed the change in medical students attitudes toward the underserved by computing a weighted mean effect size of studies reporting scores from validated scales. The research team performed a meta-analysis for the sociodemographic and educational factors associated with medical students attitudes toward and/or intention to work with the underserved. Results Fifty-five articles met the inclusion criteria, including a total of 109,647 medical students. The average response rate was 73.2%. Most of the studies were performed in the USA (n = 45). We observed a significant decline of medical students attitudes toward the underserved throughout medical education, in both US and non-US studies. A moderate effect size was observed between the first and fourth years (d = 0.51). Higher favorable medical students attitudes toward or intention to work with the underserved were significantly associated with female gender, being from an underserved community or ethnic minority, exposure to the underserved during medical education and intent to practice in primary care. Regarding educational interventions, the effectiveness of experiential community-based learning and curricula dedicated to social accountability showed the most positive outcome. Conclusions Medical students attitudes toward the underserved decline throughout medical education. Educational interventions dedicated to improving the attitudes or intentions of medical students show encouraging but mixed results. The generalizability of our results is impeded by the high number of studies from the global-North included in the review. Supplementary Information The online version contains supplementary material available at 10.1186/s12909-021-02517-x.

Neurologic care in lower- and middle-income countries is an increasing focus for the field and training of its next generation. The International Issues article features a guide for trainees seeking information on predeparture, funding, and postdeparture advice for global health rotations. The Clinical Reasoning and Teaching Image articles review the workup and management of reversible cerebral vasoconstriction syndrome, ataxia, and new-onset clonus in the setting of fever and confusion.

The use of diagnosis (DX) data is crucial to secondary use of electronic health record (EHR) data, yet accessible structured DX data often lack in accuracy. DX descriptions associated with structured DX codes vary even after recording biopsy results; this may indicate poor data quality. We hypothesized that biopsy reports in cancer care charts do not improve intrinsic DX data quality. We analyzed DX data for a manually well-annotated cohort of patients with brain neoplasms. We built statistical models to predict the number of fully-accurate (i.e., correct neoplasm type and anatomical location) and inaccurate DX (i.e. type or location contradicts cohort data) descriptions. We found some evidence of statistically larger numbers of fully-accurate (RR=3.07, p=0.030) but stronger evidence of much larger numbers of inaccurate DX (RR=12.3, p=0.001 and RR=19.6, p

Diagnostic codes are crucial for analyses of electronic health record (EHR) data but their accuracy and precision are often lacking. Although providers enter precise diagnoses into progress notes, billing standards may limit the particularity of a diagnostic code. Variability also arises from the creation of multiple descriptions for a particular diagnostic code. We hypothesized that the variability of diagnostic codes would be greater before surgical pathology results were recorded in the medical record. A well annotated cohort of patients with brain neoplasms was studied. After diagnostic pathology reporting, the odds of more distinct diagnostic descriptions were 2.30 times higher (p=0.00358), entropy in diagnostic sequences was 2.26 times higher (p=0.0259) and entropy in diagnostic precision scores was 15.5 times higher (p=0.0324). Although diagnostic codes became more distinct on average after diagnostic pathology reporting, there was a paradoxical increase in the variability of the codes selected. Researchers must be aware of the inconsistencies and variability in particularity in structured diagnostic coding despite the presence of a definitive diagnosis.

Breast cancer is the second leading cause of cancer-related mortality in women; metastasis to distant organs results in 90% of deaths for these patients. Cancer stem cells (CSCs) are considered the drivers of metastasis. Despite our current knowledge of breast CSCs, there still remains a significant challenge in managing patients with the metastatic breast cancer, underscoring the need for identifying novel regulators of breast CSCs. The hedgehog pathway is an important mediator of stem cells; however, the effect of truncated glioma-associated oncogene homolog 1 (tGLI1), a nuclear effector of the hedgehog pathway and a gain-of-function GLI1 transcription factor, on breast CSCs has never been investigated. Herein, we investigated whether tGLI1 is implicated in breast CSCs by evaluating tGLI1 expression levels in cells grown as monolayer versus mammospheres, as a representation of the stem cell population, and found tGLI1 to be induced in mammosphere culture. Overexpression of tGLI1 promoted mammosphere-forming ability of breast cancer cells, as well as, increased the breast CSC population defined by CD44high/CD24low expression. Further, tGLI1 overexpression transformed normal mammary epithelial cells resulting in increased mammosphere formation and enhanced anchorage-independent growth of immortalized human mammary epithelial HMLE cells. Functional and biochemical assays further showed that tGLI1 promotes breast CSC self-renewal by transcriptional activation of stemness genes including a novel tGLI1 target gene, OCT4, a recently reported tGLI1 target gene (CD44), and known GLI1 target genes (Nanog and SOX2). Bioinformatic analysis of breast cancer patient datasets revealed that activated tGLI1 is associated with shortened time to develop metastasis to the lung, bone, and brain. Furthermore, tGLI1 activation is enriched in HER2-enriched and triple-negative breast cancers, the subtypes with the highest propensity to metastasize, compared to luminal subtypes. Gene Set Enrichment Analysis showed that high tGLI1 activation is enriched in breast cancer with high gene signatures of breast CSCs, radioresistance, and metastasis. We further validated these results by immunohistochemical staining of paired primary breast tumors with lymph node metastases and found that that expression of tGLI1, but not GLI1, was increased in lymph node metastases and that tGLI1 was expressed at higher levels (84-91%) of lymph node-positive metastatic HER2-enriched and triple-negative breast tumors. Lastly, tGLI1 knockdown resulted in decreased mammosphere formation of breast cancer cells and decreased expression of stemness genes, OCT4, CD44, and Nanog. Taken together, these findings establish a novel role that tGLI1 plays in mediating breast CSCs and implicate tGLI1 in facilitating breast cancer metastasis. Citation Format: Sherona R. Sirkisoon, Richard L. Carpenter, Tadas Rimkus, Daniel Doheny, Dongqin Zhu, Noah R. Aguayo, Marlyn Anguelov, Austin Arrigo, Fei Xing, Michael Chan, Jimmy Ruiz, Linda J. Metheny-Barlow, Roy Strowd, Jiayuh Lin, Boris C. Pasche, Waldemar Debinski, Kounosuke Watabe, Hui-Wen Lo. Tumor-specific gain-of-function tGLI1 transcription factor is a novel mediator of breast cancer stem cells and a novel transcriptional activator of cancer stemness genes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3689.