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International audience; Cutaneous melanomas are exceptional in children and represent a variety of clinical situations, each with a different prognosis. In congenital nevi, the risk of transformation is correlated with the size of the nevus. The most frequent type is lateral transformation, extremely rare before puberty, reminiscent of a superficial spreading melanoma (SSM) ex-nevus. Deep nodular transformation is much rarer, can occur before puberty, and must be distinguished from benign proliferative nodules. Superficial spreading melanoma can also arise within small nevi, which were not visible at birth, usually after puberty, and can reveal a cancer predisposition syndrome (CDKN2A or CDK4 germline mutations). Prognosis is correlated with classical histoprognostic features (mainly Breslow thickness). Spitz tumors are frequent in adolescents and encompass benign (Spitz nevus), intermediate (atypical Spitz tumor), and malignant forms (malignant Spitz tumor). The whole spectrum is characterized by specific morphology with spindled and epithelioid cells, genetic features, and an overall favorable outcome even if a regional lymph node is involved. Nevoid melanomas are rare and difficult to diagnose clinically and histologically. They can arise in late adolescence. Their prognosis is currently not very well ascertained. A small group of melanomas remains unclassified after histological and molecular assessment.

The recent WHO classification of skin tumors has underscored the importance of acknowledging intermediate grade melanocytic proliferations. A multistep acquisition of oncogenic events drives the progressive transformation of nevi into melanomas. The various pathways described are modulated by the initial oncogenic drivers that define the common, blue, and Spitz nevi groups. Intermediate lesions are most often the result of a clonal evolution within such nevi. Based on this established classification, we have suggested for each pathway a practical diagnostic approach, benefiting from the recently developed molecular tools, both in the setting of general pathology labs and expert centers. Moreover, recommendations regarding the re-excision and clinical follow-up are given to support decision-making in multidisciplinary tumor boards.

Fusions of ALK, ROS1, NTRK1, NTRK3, RET, MET, MERTK, FGFR1, ERBB4, LCK, BRAF, MAP3K8, MAP3K3, and PRKDC and mutation of HRAS have so far been discovered as the genetic alterations associated with the pathogenesis of Spitz neoplasms. This report presents the first case of NTRK2-rearranged Spitz/Reed nevus. The patient was a 39-year-old male with a pigmented macule rapidly growing on his shoulder. Histopathologically, the lesion was a junctional melanocytic nevus composed of large nests of spindled melanocytes with abundant eosinophilic cytoplasm associated with a hyperplastic epidermis. These findings fulfilled the diagnostic criteria of a pigmented spindle cell nevus of Reed (variant of Spitz nevus). Immunohistochemistry for pan-Trk revealed diffuse cytoplasmic positivity in the tumor cells, but immunoexpression of ALK, ROS1, and BRAF V600E was not seen. A novel, in-frame, TFG-NTRK2 fusion was identified by RNA sequencing. This case report expands the list of genetic alterations in Spitz neoplasms and the spectrum of NTRK2-rearranged tumors.

Summary Background Treatment of locally advanced rectal cancer with chemoradiotherapy, surgery, and adjuvant chemotherapy controls local disease, but distant metastases remain common. We aimed to assess whether administering neoadjuvant chemotherapy before preoperative chemoradiotherapy could reduce the risk of distant recurrences. Methods We did a phase 3, open-label, multicentre, randomised trial at 35 hospitals in France. Eligible patients were adults aged 18–75 years and had newly diagnosed, biopsy-proven, rectal adenocarcinoma staged cT3 or cT4 M0, with a WHO performance status of 0–1. Patients were randomly assigned (1:1) to either the neoadjuvant chemotherapy group or standard-of-care group, using an independent web-based system by minimisation method stratified by centre, extramural extension of the tumour into perirectal fat according to MRI, tumour location, and stage. Investigators and participants were not masked to treatment allocation. The neoadjuvant chemotherapy group received neoadjuvant chemotherapy with FOLFIRINOX (oxaliplatin 85 mg/m2, irinotecan 180 mg/m2, leucovorin 400 mg/m2, and fluorouracil 2400 mg/m2 intravenously every 14 days for 6 cycles), chemoradiotherapy (50 Gy during 5 weeks and 800 mg/m2 concurrent oral capecitabine twice daily for 5 days per week), total mesorectal excision, and adjuvant chemotherapy (3 months of modified FOLFOX6 [intravenous oxaliplatin 85 mg/m2 and leucovorin 400 mg/m2, followed by intravenous 400 mg/m2 fluorouracil bolus and then continuous infusion at a dose of 2400 mg/m2 over 46 h every 14 days for six cycles] or capecitabine [1250 mg/m2 orally twice daily on days 1–14 every 21 days]). The standard-of-care group received chemoradiotherapy, total mesorectal excision, and adjuvant chemotherapy (for 6 months). The primary endpoint was disease-free survival assessed in the intention-to-treat population at 3 years. Safety analyses were done on treated patients. This trial was registered with EudraCT (2011-004406-25) and ClinicalTrials.gov ( NCT01804790 ) and is now complete. Findings Between June 5, 2012, and June 26, 2017, 461 patients were randomly assigned to either the neoadjuvant chemotherapy group (n=231) or the standard-of-care group (n=230). At a median follow-up of 46·5 months (IQR 35·4–61·6), 3-year disease-free survival rates were 76% (95% CI 69–81) in the neoadjuvant chemotherapy group and 69% (62–74) in the standard-of-care group (stratified hazard ratio 0·69, 95% CI 0·49–0·97; p=0·034). During neoadjuvant chemotherapy, the most common grade 3–4 adverse events were neutropenia (38 [17%] of 225 patients) and diarrhoea (25 [11%] of 226). During chemoradiotherapy, the most common grade 3–4 adverse event was lymphopenia (59 [28%] of 212 in the neoadjuvant chemotherapy group vs 67 [30%] of 226 patients in the standard-of-care group). During adjuvant chemotherapy, the most common grade 3–4 adverse events were lymphopenia (18 [11%] of 161 in the neoadjuvant chemotherapy group vs 42 [27%] of 155 in the standard-of-care group), neutropenia (nine [6%] of 161 vs 28 [18%] of 155), and peripheral sensory neuropathy (19 [12%] of 162 vs 32 [21%] of 155). Serious adverse events occurred in 63 (27%) of 231 participants in the neoadjuvant chemotherapy group and 50 (22%) of 230 patients in the standard-of-care group (p=0·167), during the whole treatment period. During adjuvant therapy, serious adverse events occurred in 18 (11%) of 163 participants in the neoadjuvant chemotherapy group and 36 (23%) of 158 patients in the standard-of-care group (p=0·0049). Treatment-related deaths occurred in one ( Interpretation Intensification of chemotherapy using FOLFIRINOX before preoperative chemoradiotherapy significantly improved outcomes compared with preoperative chemoradiotherapy in patients with cT3 or cT4 M0 rectal cancer. The significantly improved disease-free survival in the neoadjuvant chemotherapy group and the decreased neurotoxicity indicates that the perioperative approach is more efficient and better tolerated than adjuvant chemotherapy. Therefore, the PRODIGE 23 results might change clinical practice. Funding Institut National du Cancer, Ligue Nationale Contre le Cancer, and R&D Unicancer.

Spitz tumors are genetically associated with activating HRAS point mutations or fusions of either ALK, ROS1, NTRK1, NTRK3, RET, MET, MERTK, LCK, BRAF, MAP3K8, or MAP3K3. All these driver gene alterations are mutually exclusive. We report two cases of agminated Spitz naevi with a GOPC-ROS1 fusion. Both cases occurred on the lower limb of young adults. Since adolescence, pigmented or pink-colored papules have been periodically arising in a limited area of skin. In one case, an ill-defined hyperpigmented macule known since childhood was present in the background. Morphologically, at least five lesions were analyzed from each patient. In one case, all were predominantly junctional pigmented Spitz naevi, and in the other case, all were compound unpigmented Spitz naevi. No atypical features were present. RNA-sequencing revealed a GOPC-ROS1 gene translocation in both cases. Split signals of ROS1 gene in fluorescence in situ hybridization were observed not only in the nests of spitzoid melanocytes but also in the bland basal melanocytes surrounding the proliferations. These findings suggest the presence of a GOPC-ROS1 mosaicism in melanocytes with further emergence of agminated Spitz naevi potentially triggered by other genetic alterations. This expands the spectrum of genetic anomalies described in agminated Spitz naevi and our understanding of the mechanisms involved in their emergence.

The genetic anomalies associated with the agminated variant of Spitz nevus have so far been limited to HRAS G13R mutations, especially when arising within a nevus spilus. A previous report exposed the case of a man with a giant pigmented macule involving his upper right limb and trunk. Since childhood, Spitz nevi have been periodically arising, within the pigmented area. The histopathology of several lesions displayed the usual criteria of junctional, compound, or intradermal Spitz nevi with a diversity of cytomorphological and architectural features. Some lesions spontaneously regressed. Genetic studies confirmed in three lesions an identical translocation involving TRPM1, PUM1, and LCK. No mutations in HRAS, NRAS, BRAF, or other known fusion genes linked to Spitz nevus were detected. LCK break-apart fluorescence in situ hybridization confirmed the rearrangement was present not only in the melanocytic proliferation but also in the surrounding non-spitzoid melanocytes. This report expands the list of genetic alterations involved both in giant congenital macules and in agminated Spitz nevi, and also extends the concept of mosaicism in melanocytes to gene translocations.

Recurrent activating Gαq mutations in the spectrum of blue nevi have been well studied. However, the clinicopathologic characteristics of the recently described CYSLTR2-mutant and PLCB4-mutant blue nevi remain limited, owing to their rarity. Herein, we present 7 CYSLTR2-mutant melanocytic neoplasms, including 1 cellular blue nevus, 4 atypical cellular blue nevi, and 2 blue nevus-like melanomas. They occurred on the scalp, breast, flank, forearm, thigh, leg, and ankle of 3 male patients and 4 female patients, with a median age of 43 (25 to 81) years at diagnosis. Five exhibited an exophytic growth, and 6 were heavily pigmented. A fascicular arrangement of medium to large spindle melanocytes was seen in 6 cases, but epithelioid cytology was present in only 2 cases, one of them being focal. A junctional component was present in 3 cases. Immunoreactivity for HMB45 was diffusely present, except in 1 cellular blue nevus. BAP1 nuclear immunoexpression was lost in 1 melanoma case. A canonical CYSLTR2 L129Q hotspot mutation was present in all cases. Altogether, these histopathologic findings suggest that CYSLTR2-mutant melanocytic blue neoplasms frequently exhibit a heavily pigmented exophytic tumor with a silhouette resembling "pigmented epithelioid melanocytoma" rather than usual cellular blue nevus. Moreover, most of these tumors were not clinically recognized as blue nevi and not located in the classic topography of cellular blue nevus aside from the scalp. However, a fascicular arrangement of medium to large-sized spindled melanocytes, as well as a lack of epithelioid or nevoid melanocytes, could be potential diagnostic clues to morphologically distinguish CYSLTR2-mutant tumors from "pigmented epithelioid melanocytoma."

Peritoneal carcinomatosis (pcm) in metastatic pancreatic ductal adenocarcinomas (mpdac) is frequently encountered in day-to-day practice, but rarely addressed in the literature. The objective of the present study was to describe the management and outcome of patients diagnosed with pcm. Data for all consecutive patients with mpdac treated in our centre between 1 January 2014 and 31 August 2015 were analyzed retrospectively. Computed tomography imaging was centrally reviewed by a dedicated radiologist to determine the date of pcm diagnosis. The analysis included 48 patients. Median age in the group was 61 years, and 41 patients had an Eastern Cooperative Oncology Group performance status (ecog ps) of 0&ndash, 1. All patients presented with pcm either synchronously (group 1) or metachronously (group 2). Those groups differed significantly by baseline ecog ps and neutrophil-to-lymphocyte ratio (nlr), with ecog ps being poorer and nlr being higher in group 1. In addition to pcm, the main sites of metastasis were liver (62.5%) and lungs (31.3%). First-line chemotherapy in 36 patients (75%) was folfirinox (fluorouracil&ndash, irinotecan&ndash, leucovorin&ndash, oxaliplatin). The median overall survival for the entire population was 10.81 months [95% confidence interval (ci): 7.16 months to 14.16 months], it was 13.17 months (95% ci: 5.9 months to 15.4 months) for patients treated with folfirinox. Median overall survival was 7.13 months (95% ci: 4.24 months to 10.41 months) for patients in group 1 and 14.34 months (95% ci: 9.79 months to 19.91 months) for patients in group 2, p = 0.1296. Compared with other metastatic sites, synchronous pcm seems to be a poor prognostic factor. It could be more frequently associated with a poor ecog ps and a nlr greater than 5 in this group of patients. In patients with mpdac and pcm, either synchronous or metachronous, folfirinox remains an efficient regimen.

A cutaneous melanocytic tumor with morphologic overlap with clear cell sarcoma, but defined by CRTC1-TRIM11 gene fusion, was recently described in a series of five adult patients. Here, we expand the clinicopathologic features of this entity by four additional cases which include pediatric presentation, exophytic growth, and propensity to occur on the head. Patients (2F; 2M) had a median age of 41 years (range 11-59). Sites of involvement included leg, ear, and face. Tumors were circumscribed, unencapsulated, mostly limited to the dermis, and varied from 5 to 35 mm. One case was exophytic. Lesional cells were arranged in nests and fascicles, and were monomorphic and fusiform with moderate pale to clear cytoplasm, occasional nuclear pseudo-inclusions, and small to prominent nucleoli. Mitotic rate was variable (rare to 12/10 HPF, median 3/10 HPF). The pediatric case showed increased nuclear pleomorphism, tumor necrosis, and mitotic figures. All cases showed strong, diffuse nuclear staining for SOX10, but were negative or focal for S100 protein, HMB45 and Melan-A expression. Cases were positive by FISH technique and/or RNA sequencing for a TRIM11 rearrangement/fusion, and negative for EWSR1 rearrangement. This series is presented to aid in further characterization of this novel melanocytic tumor.

Background Multiple BRCA1-associated protein 1 (BAP1)-inactivated melanocytic tumors (BIMTs) have been associated with a familial cancer syndrome involving germline mutations in BAP1. Objectives We sought to describe the clinical and dermoscopic features of BIMTs. Methods This was a retrospective, multicenter, case-control study. Participating centers contributed clinical data, dermoscopic images, and histopathologic data of biopsy-proven BIMTs. We compared the dermoscopic features between BIMTs and control patients. Results The dataset consisted of 48 BIMTs from 31 patients (22 women; median age 37 years) and 80 control patients. Eleven patients had a BAP1 germline mutation. Clinically, most BIMTs presented as pink, dome-shaped papules (n = 24). Dermoscopically, we identified 5 patterns: structureless pink-to-tan with irregular eccentric dots/globules (n = 14, 29.8%); structureless pink-to-tan with peripheral vessels (n = 10, 21.3%); structureless pink-to-tan (n = 7, 14.9%); a network with raised, structureless, pink-to-tan areas (n = 7, 14.9%); and globular pattern (n = 4, 8.5%). The structureless with eccentric dots/globules pattern and network with raised structureless areas pattern were only identified in BIMT and were more common in patients with BAP1 germline mutations (P Limitations Limitations included our small sample size, retrospective design, the absence of germline genetic testing in all patients, and inclusion bias toward more atypical-looking BIMTs. Conclusions Dome-shaped papules with pink-to-tan structureless areas and peripheral irregular dots/globules or network should raise the clinical suspicion for BIMT.

e21592 Background: While 10% of melanomas occur in a context suggesting hereditary predisposition, a clear molecular explanation has only been established for approximately 20% of families. In the course of clinical care, we identified a new CTNNA1 truncating germline mutation in a family affected by multiple early-onset melanomas. Methods: NGS and CGH-array were performed on the index case’s melanoma, followed by Sanger sequencing of the germline DNA of relatives. Immunochemistry (IHC) was employed to evaluate the level of αE-catenin (encoded by CTNNA1) in the family's samples. Stable CTNNA1 knockout human melanoma cell lines were generated to investigate the functional effects of CTNNA1 loss. Functional assays, including colony formation, 3-D tumor spheroid formation, wound healing, and transwell invasion were performed, as well as electron microscopy and RNAsequencing (RNAseq). CTNNA1 mutational status was determined in several databases and further sequencing of CTNNA1 in a DNA bank of families with multiple melanomas was done. Results: While the allele frequency in the index patient’s tumoral DNA was compatible with a germline mutation, the CTNNA1 F611fs*10 mutation was subsequently found cosegregating with individuals affected by melanoma in the family. CGH array on tumor DNA identified a segmental loss on chromosome 5, leading to a loss of heterozygosity of CTNNA1, resulting in a loss of αE-catenin observed by IHC. Clinically, the mean age of first melanoma diagnosis was 29,7 years (range: 18-56), 2 were metastatic, and the others were SSM (superficial spreading melanoma) in situ (n = 3) or Breslow index 0,56 mm (n = 1). Functional assays performed on CTNNA1 KO melanoma cell lines showed a loss of cell-to-cell adhesion phenotype, in accordance with the altered adherens junctions observed by electron microscopy, and the specific pathway enrichments observed by RNAseq. This specific phenotype could be rescued by transfection with a plasmid containing wild-type CTNNA1, as opposed to the CTNNA1 F611fs* plasmid. Germline CTNNA1 mutations are rare as none could be further identified in a DNA bank of 27 multiple melanoma families. In a database of 4743 melanomas somatically sequenced for CTNNA1, 131 of them had a CTNNA1 alteration (2,76%), with a median tumor mutational burden of 44 mut/MB of DNA (range from 0 to 451). Among them, 15 alterations were predicted to be inactivating, including 7 associated with a BRAF or NRAS activating mutation. Conclusions: Altogether, our results strongly support that CTNNA1 loss of function predisposes to melanoma formation characterized by a decreased cell adhesion. Since germline CTNNA1 alterations have already been implicated in lobular breast cancers and hereditary diffuse gastric cancers, CTNNA1 likely constitutes a tumor suppressor gene involved in familial melanoma, thus broadening the spectrum of syndromes associated with this gene.

International audience; Spitz nevi are indolent melanocytic tumors arising preferentially during and after childhood. Over the last decades, recurrent oncogenic drivers, sparsely detected in melanoma, were identified in Spitz melanocytic proliferations. Therefore, the detection of such drivers appears as a relevant diagnostic tool to distinguish both entities. Interestingly, morphologic features might correlate with the oncogenic drivers. Thus, the goal of this study was to assess the performances of previously identified morphological criteria to predict the presence of specific drivers. In total, 352 Spitz melanocytic proliferations either with a genetically identified oncogenic driver or investigated for ALK, ROS1, and NTRK1 overexpression by immunohistochemistry were enrolled in the present study. The microscopic features of the cases were assessed blindly with regards to the molecular status and, performances of previously described morphological criteria to predict the molecular status were assessed applying the likelihood-ratio test (LHR). Overall, an oncogenic driver was identified in 76% of the cases (n = 268/352). No microscopic features allowed the reliable prediction of ROS1- and NTRK1-overexpressing cases. By contrast, a plexiform pattern can contribute to the recognition of ALK-overexpressing cases (LHR(+) = 6.14). Importantly, the pseudo-schwannoma variant was highly suggestive of NTRK3-rearranged cases (LHR(+) = 43). Moreover, atypical/malignant tumor (LHR(+) = 5.18), severe cellular atypia (LHR(+) = 5.07), and p16 loss (LHR(+) = 14) contribute to the recognition of MAP3K8-rearranged cases, while the presence of a sheet-like architecture (LHR(+) = 5.39) and a marked fibrosis of the stroma (LHR(+)=5.06) were predictive of BRAF-fused tumors. To conclude, our study confirms ALK-overexpressing, NTRK3-, MAP3K8-, and BRAF-rearranged cases harbored distinct morphologic features allowing their microscopic recognition.

Clear cell morphology is an uncommon finding in tumors. A subset of clear cell neoplasms also shows melanocytic differentiation, including clear cell sarcoma, PEComa, and some subtypes of renal cell carcinoma. A hallmark of these tumor types is the activation of a member of the MIT/TFE family of transcription factors, which includes MITF, TFE3, TFEB, and TFEC. Microphthalmia transcription factor (MITF is the master regulator of melanin synthesis, while TFEB plays a critical role in lysosome biogenesis. Cytogenetic translocations involving TFE3 and TFEB are now well described in multiple tumor types, but there has been little evidence to suggest similar regulation of MITF. Here we describe a series of 7 clear cell cutaneous neoplasms with melanocytic differentiation that are characterized by ACTIN-MITF gene fusions, either ACTB-MITF or ACTG1-MITF. The chromosomal breakpoints preserve MITF's dimerization and transcriptional activation domains, suggesting that these fusion proteins likely result in hyperactive MITF function, analogously to the previously reported TFE3 and TFEB fusions. Our findings indicate that MITF gene rearrangements may be key drivers of tumor pathogenesis and expand the spectrum of neoplasia associated with the MIT/TFE family.

Resume Introduction Les cas de melanomes se developpant chez le nourrisson sont rares et de diagnostic difficile. Nous rapportons le cas d’une enfant presentant un naevus congenital geant du cuir chevelu complique d’un melanome d’apparition precoce explore par les nouveaux outils diagnostiques disponibles. Observation Notre patiente presentait a la naissance une tumeur congenitale cervico-mandibulaire de 15 cm de grand axe avec extension para-pharyngee et osteolyse sous-jacente. L’histologie a 7 mois de vie, couplee a de l’immunohistochimie (IHC), concluait a un melanome developpe sur un naevus congenital, en raison de la presence de nombreuses atypies cytonucleaires, de mitoses, de foyers de necrose et d’une forte expression de P53 ainsi que d’un index de proliferation (Ki67) eleve. Le bilan d’extension etait negatif. Des chirurgies iteratives et une surveillance etaient realisees jusqu’a l’âge de 7 ans. A cette echeance, l’absence de metastases conduisait a realiser de nouvelles analyses sur les prelevements initiaux pour authentifier le diagnostic. L’etude de l’expression de certains facteurs de transcription par IHC recemment decrite, l’hybridation genomique comparative et la spectrometrie de masse guidee par l’histologie, bien que suspects, ne permettaient pas, a eux seuls, de conclure formellement a une lesion maligne. A 7 ans et demi, l’enfant developpait des metastases hepatiques et pulmonaires traitees par l’association ipilimumab + nivolumab. L’enfant decedait 5 mois plus tard. Conclusion Ce cas illustre la complexite du diagnostic de melanome chez le nourrisson et la possibilite d’une evolution metastatique tardive. Il rappelle la necessite d’un avis d’expert et parfois de combiner plusieurs outils pour affirmer le diagnostic et adapter la prise en charge.

The presence of melanocytic differentiation in tumors of non-melanocyte origin is uncommon and is typically associated with the overexpression of MITF, the master regulator of melanin synthesis, or another member of the MIT/TFE3 family. In clear cell sarcoma, the presence of either an EWSR1-ATF1 or EWSR1-CREB1 translocation-derived fusion protein is thought to drive melanocytic differentiation by directly stimulating the expression of MITF. Here, we describe a clear cell neoplasm with melanocytic differentiation that is characterized by a novel MITF-CREM gene fusion. CREM is the third member of the ATF1/CREB1/CREM family, and the nature of the MITF-CREM fusion appears analogous to the EWSR1-ATF1 and EWSR1-CREB1 fusions. Thus, this MITF-CREM-rearranged clear cell tumor represents a novel entity with morphologic, immunohistochemical, and molecular similarity to clear cell sarcoma.

We report a series of 6 melanocytic proliferations harboring both NRAS and IDH1 hotspot mutations. Clinically, there was no specific sex-ratio, ages ranged from 18 to 85 years, and the trunk and limbs were the most affected localizations. In half of the cases, progressive modification of a pre-existing nevus was reported. Morphologically, all tumors were predominantly based in the dermis and the most striking pathologic finding was the presence of a background architecture of congenital-type nevi with a superimposed biphasic pattern formed by dendritic pigmented melanocytes surrounding areas of nevoid melanocytes. This finding was further underscored by HMB45 staining, which was positive in the dendritic cells and negative in the nevoid melanocytes. Four cases displayed increased cellularity and 1 case showed increased dermal mitotic activity. DNA and RNA sequencing revealed NRAS and IDH1 comutations in all 6 cases, with homogenous expression data according to unsupervised clustering analysis. Array-comparative genomic hybridization revealed no copy number alteration for the 2 most cellular and mitogenic cases. All were surgically excised, available follow-up for 2 patients showed no relapse nor metastases. We hypothesize that the IDH1 mutation is a secondary event in a pre-existing NRAS-mutated nevus and could be in part responsible for the emergence of a pigmented dendritic dermal component. So far, such comutations have been reported in one benign melanocytic nevus and several melanomas. This combination could represent a new subgroup of intermediate prognosis (melanocytoma) with a distinctive morphology. Further acquisition of genomic anomalies could progressively lead to malignant transformation.

A subset of Spitz tumors harbor fusions of NTRK3 with ETV6, MYO5A, and MYH9. We evaluated a series of 22 melanocytic tumors in which an NTRK3 fusion was identified as part of the diagnostic workup. Tumors in which NTRK3 was fused to ETV6 occurred in younger patients, were predominantly composed of epithelioid melanocytes, and were classified by their histopathologic features as Spitz tumors. In contrast, those in which NTRK3 was fused to MYO5A were predominantly composed of spindled melanocytes arrayed in fascicles with neuroid features such as pseudo-Verocay bodies. To further investigate the effects of the fusion kinases ETV6-NTRK3 and MYO5A-NTRK3 in melanocytes, we expressed them in immortalized melanocytes and determined their subcellular localization by immunofluorescence. ETV6-NTRK3 was localized to the nucleus and diffusely within the cytoplasm and caused melanocytes to adopt an epithelioid cytomorphology. In contrast, MYO5A-NTRK3 appeared excluded from the nucleus of melanocytes, was localized to dendrites, and resulted in a highly dendritic cytomorphology. Our findings indicate that ETV6-NTRK3 and MYO5A-NTRK3 have distinct subcellular localizations and effects on cellular morphology.

Due to its high proclivity to metastasize, and despite the recent development of targeted and immune therapy strategies, melanoma is still the deadliest form of skin cancer. Therefore, understanding the molecular mechanisms underlying melanoma invasion remains crucial. We previously characterized Tspan8 for its ability to prompt melanoma cell detachment from their microenvironment and trigger melanoma cell invasiveness, but the signaling events by which Tspan8 regulates the invasion process still remain unknown. Here, we demonstrated that β-catenin stabilization is a molecular signal subsequent to the onset of Tspan8 expression, and that, in turn, β-catenin triggers the direct transcriptional activation of Tspan8 expression, leading to melanoma invasion. Moreover, we showed that β-catenin activation systematically correlates with a high expression of Tspan8 protein in melanoma lesions from transgenic Nras; bcat* mice, as well as in deep penetrating naevi, a type of human pre-melanoma neoplasm characterized by a combined activation of β-catenin and MAP kinase signaling. Overall, our data suggest that β-catenin and Tspan8 are part of a positive feedback loop, which sustains a high Tspan8 expression level, conferring to melanoma cells the invasive properties required for tumor progression and dissemination.

Melanocytic tumors rarely display extensive dermal myxoid deposits except in the myxoid variant of melanoma. We describe in 4 patients the unusual association of morphologic and genetic features. All cases occurred in males and were located on the limbs or proximal girdle area. Age at diagnosis ranged from 8 to 47 years. Size ranged from 6 to 11 mm. Microscopic analysis showed compound, but mainly dermal melanocytic nevi, all presenting a deep dermal expansion with fascicules of amelanotic spindled cells floating in a myxoid background. Cytologic atypia and mitotic activity were low. The superficial portion was either of spitzoid or nevoid cytology with a limited junctional component. In the initial case, the dermal myxoid component was predominant with rare, barely visible, superficial melanocytic nests. This peculiar morphology was responsible for a delayed diagnostic, which required an extensive panel of antibodies ruling out most, potentially myxoid, soft tissue tumors. We later observed the presence of similar, but more limited, dermal morphologic features in 3 other cases. Immunohistochemistry in the deep myxoid areas was melanA, ALK, SOX10, and MiTF. Molecular studies confirmed the ALK rearrangement by an ALK break-apart fluorescence in situ hybridization technique and by RNA sequencing. The latter identified 4 different 5'-fusion partners. Two gene fusions were undescribed: FBXO28(e2)-ALK(e19) and NPAS2(e2)-ALK(e19), and 2 previously described: TPM3(e7)-ALK(e20) and PPFIBP1(e9)-ALK(e19). No relapse or metastatic evolution was seen during follow-up (3 to 24 mo). We denominated this potentially challenging new variant of compound nevus linked to a kinase fusion: Melanocytic Myxoid Spindle Cell Tumor with ALK Rearrangement.

We report 5 cases of primary intradermal nodular unpigmented tumors with a melanocytic immunophenotype associated with a novel CRTC1-TRIM11 fusion. Clinically, the cutaneous nodules were slowly growing in 3 women and 2 men (25 to 82 y old, median, 28 y) with no specific topography. Lesion size ranged from 4 to 12 mm (median, 5 mm). The tumors were strictly located in the dermis with a nodular pattern. The cells were arranged in confluent nests and fascicules. Central fibronecrotic areas were present in 2 cases. Cells were medium to large, sometimes multinucleated, and presented a spindled and epithelioid cytology with prominent nucleoli. Cytonuclear atypia was constant, and mitotic activity in hotspot areas ranged from 1 to 5/mm². Immunohistochemistry found a constant positivity with S100, MiTF, and Sox10, and a heterogenous staining by MelanA or HMB45. NTRK1 was strongly positive in 3 cases. In all cases, RNA sequencing found an invariable CRTC1(e1)-TRIM11(e2) fusion, confirmed by fluorescent in situ hybridization techniques with a TRIM11 break-apart probe. In 4/4 cases, nuclear TRIM11 expression was positive by immunohistochemistry. Fluorescent in situ hybridization techniques showed no rearrangement of NTRK1 or EWSR1, and array-comparative genomic hybridization displayed no alteration (1 case) or only a whole chromosome 7 gain (2 cases) when performed. No relapse or metastatic event was observed during follow-up [3 to 72 months (median, 14 mo)]. Cutaneous clear cell sarcoma was the main differential diagnosis. Overlapping morphologic features previously described in primary dermal melanomas and paraganglioma-like melanocytic tumors were present. The CRTC1-TRIM11 fusion appears to be specific of an unpigmented nodular tumor combining a melanocytic phenotype and low-grade tumor behavior.

The current classification of melanocytic tumors includes clinical, pathological, and molecular data. A subset of lesions remains difficult to classify according to these complex multilayer schemes. We report two cases of deeply infiltrating melanomas with a sclerosing background. The first case occurred on the back of a middle-aged man appearing clinically as a dermatofibroma. The architectural and cytological aspects resembled those of a desmoplastic melanoma but the strong expression of both melanA and HMB45, two stainings usually reported as negative in this entity, raised the question of an alternate diagnosis. The second case was a large, slowly growing, perivulvar tumor in a middle-aged woman. The morphology was complex with a central junctional spitzoid pattern associating an epidermal hyperplasia with large nests of large spindled melanocytes. The dermal component was made of deeply invasive strands and nests of nevoid unpigmented melanocytes surrounded by fibrosis; a perineural invasion was present at the periphery of the lesion. In both cases, aCGH found, among many other anomalies, a chromosomal breakpoint at the BRAF locus. RNA sequencing identified in both an AKAP9-BRAF gene fusion. A complementary resection was performed and no relapses have been observed in the respectively 15 and 6 months of follow-up. Both of these melanomas remained unclassified. We further review the variety of melanocytic tumors associated with such BRAF fusions.

Resume Nous rapportons le cas d’un homme âge de 57 ans hospitalise pour la prise en charge chirurgicale d’un nodule vesiculaire fixant a la tomographie par emission de positrons. Celui-ci est decouvert fortuitement au cours du suivi d’un melanome cutane. Une cholecystectomie est effectuee. L’examen microscopique montre une infiltration de toute la paroi de la vesicule biliaire par une proliferation fortement pigmentee faite de cellules allongees aux noyaux nucleoles, anisocaryotiques avec de nombreuses mitoses atypiques. L’immunohistochimie confirme la nature melanocytaire de cette proliferation avec un marquage de l’HMB-45, de la P-S100 et du Melan-A. Devant la suspicion de metastase vesiculaire d’un melanome cutane, une etude immunohistochimique (p16, desmine et BRAFV600E) et moleculaire (sequencage du gene BRAF) complementaire est effectuee et est compatible avec une localisation secondaire. Le diagnostic de metastase vesiculaire d’un melanome est pose. Les localisations secondaires vesiculaires de melanomes sont exceptionnelles. Le but de notre travail est d’en rapporter un cas avec sa caracterisation immunohistochimique et moleculaire, d’effectuer une synthese de la revue des cas publies dans la litterature et d’envisager le principal diagnostic differentiel morphologique (le melanome primitif de la vesicule biliaire).

Melanocytic BAP1-associated intradermal tumors (MBAITs) can either be sporadic or associated with a cancer-predisposition syndrome. In this study we explored the clinical status of 136 patients in which at least one MBAIT was found. 49/136 (36%) of them gave their signed consent for an oncogenetic BAP1 blood test. 28/136 patients (20%) diagnosed with an MBAIT had other MBAITs and/or a personal or familial history of BAP1-related cancers that could clinically designate them as potential carriers of a BAP1 germline mutation. 17 of these 28 patients underwent oncogenetic testing. A deleterious mutation of BAP1 was confirmed in 12/17 cases. 4/17 cases were wild-type; all had a single MBAIT and a history of skin melanoma. A variant of unknown significance was found in one case with multiple MBAITs. Among the 12 mutated cases, multiple MBAITs were present in 10/12 cases and were the only clinical sign in 4/12 cases. The remaining 32/49 blood-tested cases with an isolated MBAIT were wild type for BAP1 in 25/32 cases or showed a variant of unknown significance in 7/32 cases. We recommend, following the diagnosis of a MBAIT, performing a BAP1 immunohistochemistry in all other cutaneous melanocytic tumors removed previously or simultaneously and all skin melanomas. This screening could help clinicians prioritize which patients would most benefit from oncogenetic testing.

// Manale El Kharbili 1, 2, 3, 4 , Clement Robert 1, 2, 3 , Tiffany Witkowski 5, 6 , Emmanuelle Danty-Berger 7 , Laetitia Barbollat-Boutrand 1, 2, 3 , Ingrid Masse 1, 2, 3 , Nicolas Gadot 8 , Arnaud de la Fouchardiere 9 , Paul C. McDonald 10 , Shoukat Dedhar 10 , Francois Le Naour 11, 12 , Francoise Degoul 5, 6 , Odile Berthier-Vergnes 1, 2, 3 1 Universite de Lyon, Lyon, France 2 Universite Lyon 1, Lyon, France 3 CNRS, UMR5534, Centre de Genetique et de Physiologie Moleculaire et Cellulaire, Villeurbanne, France 4 Current address: Department of Dermatology, University of Colorado, Aurora, Colorado, USA 5 Clermont Universite, Universite d’Auvergne, Imagerie Moleculaire et Therapie Vectorisee, Clermont-Ferrand, France 6 Inserm, U990, Clermont-Ferrand, France 7 Laboratoire CarMeN (INSERM 1060, INRA1397, INSA), Universite Lyon 1, Lyon, France 8 Universite Lyon 1, Federation de Recherche Sante Lyon-Est, ANIPATH, Faculte Laennec, Lyon, France 9 Departement de Biopathologie, Centre Leon Berard, Lyon, France 10 Department of Integrative Oncology, British Columbia Cancer Research Center, Vancouver, Canada 11 INSERM U602, Villejuif, France 12 Current address: INSERM U1193, Hopital Paul Brousse, Villejuif, France Correspondence to: Odile Berthier-Vergnes, email: odile.berthier-vergnes@univ-lyon1.fr Keywords: melanoma, matrix, integrin, tetraspanin 8, ILK Received: November 09, 2016 Accepted: January 09, 2017 Published: February 04, 2017 ABSTRACT Melanoma is well known for its propensity for lethal metastasis and resistance to most current therapies. Tumor progression and drug resistance depend to a large extent on the interplay between tumor cells and the surrounding matrix. We previously identified Tetraspanin 8 (Tspan8) as a critical mediator of melanoma invasion, whose expression is absent in healthy skin. The present study investigated whether Tspan8 may influence cell-matrix anchorage and regulate downstream molecular pathways leading to an aggressive behavior. Using silencing and ectopic expression strategies, we showed that Tspan8-mediated invasion of melanoma cells resulted from defects in cell-matrix anchorage by interacting with β1 integrins and by interfering with their clustering, without affecting their surface or global expression levels. These effects were associated with impaired phosphorylation of integrin-linked kinase (ILK) and its downstream target Akt-S473, but not FAK. Specific blockade of Akt or ILK activity strongly affected cell-matrix adhesion. Moreover, expression of a dominant-negative form of ILK reduced β 1 integrin clustering and cell-matrix adhesion. Finally, we observed a tumor-promoting effect of Tspan8 in vivo and a mutually exclusive expression pattern between Tspan8 and phosphorylated ILK in melanoma xenografts and human melanocytic lesions. Altogether, the in vitro, in vivo and in situ data highlight a novel regulatory role for Tspan8 in melanoma progression by modulating cell-matrix interactions through β1 integrin-ILK axis and establish Tspan8 as a negative regulator of ILK activity. These findings emphasize the importance of targeting Tspan8 as a means of switching from low- to firm-adhesive states, mandatory to prevent tumor dissemination.

The proliferation of cells with melanocytic lineage and a nested pattern has traditionally been regarded as a characteristic feature of a wide range of benign and malignant melanocytic proliferations. Herein, we report a series of 4 clear cell sarcomas, including 3 primary cutaneous and 1 metastatic to the skin, associated with a clear-cut intraepidermal proliferation of tumor cells representing a serious potential diagnostic pitfall. All patients were male individuals, aged from 17 to 71 years (mean: 42 y). The size of the tumors ranged from 8 to 55 mm (mean: 22.2 mm, median: 13 mm). Two tumors arose on a lower extremity and 1 each on the scalp and chest. Cutaneous metastasis developed on the limb proximal to the amputation site. Histologically, all tumors were variably circumscribed nodular or multinodular proliferations within the dermis, focally extending into the subcutis. They were composed of nests and fascicles of pale spindled and epithelioid cells with finely granular or pale cytoplasm, elongated nuclei with a single prominent nucleolus, featuring mild nuclear pleomorphism, and surrounded by delicate fibrous septa. Scattered wreath-like giant cells were present in all cases. Mitotic activity was low (mean and median: 3.5 mitoses/mm). The intraepidermal component consisted in all 4 cases of nests of tumor cells localized at the dermal-epidermal junction. Nests were well-defined and composed of spindled or epithelioid cells with irregular hyperchromatic nuclei, prominent nucleoli, and scant to moderately abundant eosinophilic to pale cytoplasm. Lentiginous proliferation of epithelioid tumor cells was coupled with focal upward migration of isolated tumor cells in a single case. By immunohistochemistry, all tumors were S100 protein, melan A, and HMB45 positive. By fluorescence in situ hybridization analysis, 3 tumors displayed rearrangements in the EWSR1 gene, whereas reverse transcriptase polymerase chain reaction confirmed EWSR1(e8)/ATF1(e4) translocation in the remaining case. In conclusion, an epidermal component in primary cutaneous clear cell sarcomas, or cutaneous metastasis of the tumor, is exceptional and represents a potential diagnostic pitfall. Careful attention to the salient morphologic features in the dermal component of the tumor, as well as confirmation of EWSR1 gene rearrangement by fluorescence in situ hybridization or reverse transcriptase polymerase chain reaction, is necessary for correct recognition of the tumor and to avoid erroneous diagnosis of a benign or malignant melanocytic proliferation.

We report a series of 21 compound blue nevi, a rare variant in the vast clinical and morphological spectrum of blue melanocytic proliferations. Clinically, they presented in young adults, with a slight female predominance. One-third were located on the dorsum of the foot. Morphologically, all cases displayed large dendritic melanocytes restricted to the deep layers of the epidermis. The compound component was central and evenly distributed. Melanocytic density ranged from scarce isolated cells to a confluent lentiginous architecture. In 12 of the 21 cases, junctional nests of small, bland, weakly pigmented melanocytes were associated. These nests became confluent in the most cellular cases. In all cases, a dermal component was immediately present underneath, mainly of cellular blue nevus-type. All cases were genetically confirmed to harbor either a GNAQ or GNA11 hotspot mutation. This study expands the morphological spectrum of blue nevi that should not be restricted to a strictly intradermal melanocytic proliferation.

International audience; Background & aims: Pancreatic ductal adenocarcinoma (PDAC) is associated with the highest incidence of venous thromboembolism (VTE) of any cancer type. However, little is known about risk factors for VTE or its outcomes in patients with PDAC.Methods: We collected data from a prospective, observational study performed at multiple centers in France from May 2014 through November 2018 (the Base Clinico-Biologique de l'Adénocarcinome Pancréatique [BACAP] study) linked to a database of patients with a new diagnosis of PDAC of any stage. Data were collected from 731 patients at baseline and during clinical follow-up or in the event of symptoms. The primary endpoint was the onset of VTE during follow-up. The secondary endpoints were progression-free survival (PFS) and overall survival (OS) times.Results: During a median follow-up of 19.3 months, 152 patients (20.79%) developed a VTE. The median time from PDAC diagnosis to the onset of VTE was 4.49 months. Cumulative incidence values of VTE were 8.07% (95% confidence interval [CI], 6.31-10.29) at 3 months and 19.21% (95% CI, 16.27-22.62) at 12 months. In multivariate analysis, PDAC primary tumor location (isthmus vs head: hazard ratio [HR], 2.06; 95% CI, 1.09-3.91; P = .027) and stage (locally advanced vs resectable or borderline: HR, 1.66; 95% CI, 1.10-2.51, P = .016; metastatic vs resectable or borderline: HR, 2.50; 95% CI, 1.64-3.79; P < .001) were independent risk factors for the onset of VTE. Patients who developed VTE during follow-up had shorter times of PFS (HR, 1.74; 95% CI, 1.19-2.54; P = .004) and OS (HR, 2.02; 95% CI, 1.57-2.60; P < .001).Conclusion: In an analysis of data from the BACAP study, we found that frequent and early onsets of VTE after diagnoses of PDAC are associated with significant decreases in times of PFS and OS. Studies are needed to determine whether primary prophylaxis of VTE in patients with PDAC will improve morbidity and mortality related to VTE. (ClinicalTrials.gov, Number: clinicaltrials.gov as number NCT02818829).

International audience; We report a series of 33 skin tumors harboring a gene fusion of the MAP3K8 gene, which encodes a serine/threonine kinase. The MAP3K8 fusions were identified by RNA sequencing in 28 cases and by break-apart FISH in five cases. Cases in which fusion genes were fully characterized demonstrated a fusion of the 5' part of MAP3K8 comprising exons 1-8 in frame to one of several partner genes at the 3' end. The fusion genes invariably encoded the intact kinase domain of MAP3K8, but not the inhibitory domain at the C-terminus. In 13 (46%) of the sequenced cases, the 3' fusion partner was SVIL. Other recurrent 3' partners were DIP2C and UBL3, with additional fusion partners that occurred only in a single tumor. Clinically, the lesions appeared mainly in young adults (2-59 years of age; median = 18), most commonly involving the lower limbs (55%). Five cases were diagnosed as Spitz nevus, 13 as atypical Spitz tumor, and 15 as malignant Spitz tumor. Atypical and malignant cases more commonly occurred in younger patients. Atypical Spitz tumors and malignant Spitz tumors cases tended to show epidermal ulceration (32%), a dermal component with giant multinucleated cells (32%), and clusters of pigmented cells in the dermis (32%). Moreover, in atypical and malignant cases, a frequent inactivation of CDKN2A (21/26; 77%) was identified either by p16 immunohistochemistry, FISH, or comparative genomic hybridization. Gene expression analysis revealed that MAP3K8 expression levels were significantly elevated compared to a control group of 57 Spitz lesions harboring other known kinase fusions. Clinical follow-up revealed regional nodal involvement in two of six cases, in which sentinel lymph node biopsy was performed but no distant metastatic disease after a median follow-up time of 6 months.

International audience; A girl, born with a posterior lumbosacral giant congenital nevus, developed a central nodule that expanded over a period of 14 months into a 10-cm pedunculated mass. Histological analysis of the mass revealed melanoma of myxoid, small round-cell type with areas of rhabdomyosarcomatous transformation confirmed by immunohistochemistry. RNA sequencing identified an in-frame SASS6(e14)-RAF1(e8) fusion in both components and the nevus. A RAF1 FISH break-apart test found a balanced rearrangement pattern in the nevus and an unbalanced pattern in the malignant areas. Wild-type status of NRAS and BRAF was confirmed by NGS techniques. The array-CGH profile displayed copy number alterations commonly found in rhabdomyosarcomas. Despite intensive treatment, widespread metastatic evolution of the melanomatous component was observed.

Activating NTRK1 fusions have been described as oncogenic events across the spectrum of Spitz tumors. Herein we report a series of 38 Spitz tumors with NTRK1 fusion. These Spitz tumors have distinctive histopathologic features characterized by filigree-like rete ridges which are elongated, thin and branched, dermal melanocytes arranged in a rosette-like configuration, and marked diminishment of melanocyte size with descent into the dermis. These features are distinct from those of other genetically defined subtypes of Spitz tumors and can aid in microscopic diagnosis and help prioritize in case selection for molecular testing in the rare patients that need targeted therapy.

As knowledge continues to develop, regular updates are necessary concerning recommendations for practice. The recommendations for the management of melanoma stages I to III were drawn up in 2005. At the request of the Societe Francaise de Dermatologie, they have now been updated using the methodology for recommendations proposed by the Haute Autorite de Sante. In practice, the principal recommendations are as follows: for staging, it is recommended that the 7th edition of AJCC be used. The maximum excision margins have been reduced to 2cm. Regarding adjuvant therapy, the place of interferon has been reduced and no validated emerging medication has yet been identified. Radiotherapy may be considered for patients in stage III at high risk of relapse. The sentinel lymph node technique remains an option. Initial examination includes routine ultrasound as of stage II, with other examinations being optional in stages IIC and III. A shorter strict follow-up period (3years) is recommended for patients, but with greater emphasis on imaging.

We report two cases of fibrous histiocytoma (FH) associated with discrete nodular aggregates of Langerhans cells (LCs) resembling Langerhans cell histiocytosis (LCH). In addition, the LCs showed positivity for BRAF V600E immunohistochemistry, a finding reported in neoplastic but not reactive LCs 1. To our knowledge, these cases represent the first published association of FH and LCH. This article is protected by copyright. All rights reserved.

International audience; Ectodysplasin receptor EDAR is seen as a typical Tumor Necrosis Factor receptor (TNFR) family member known to interact with its ligand Eda-A1, and signaling mainly through the nuclear factor-kappaB (NF-κB) and c-jun N-terminal kinases pathways. Mutations in genes that encode proteins involved in EDAR transduction cascade cause anhidrotic ectodermal dysplasia. Here, we report an unexpected pro-apoptotic activity of EDAR when unbound to its ligand Eda-A1, which is independent of NF-κB pathway. Contrarily to other death receptors, EDAR does recruit caspase-8 to trigger apoptosis but solely upon ligand withdrawal, thereby behaving as the so-called dependence receptors. We propose that pro-apoptotic activity of unbound EDAR confers it a tumor suppressive activity. Along this line, we identified loss-of-pro-apoptotic function mutations in EDAR gene in human melanoma. Moreover, we show that the invalidation of EDAR in mice promotes melanoma progression in a B-Raf mutant background. Together, these data support the view that EDAR constrains melanoma progression by acting as a dependence receptor.

BACKGROUND: The BRCA1-associated protein-1 (BAP1) tumor predisposition syndrome (BAP1-TPDS) is a hereditary tumor syndrome caused by germline pathogenic variants in BAP1 encoding a tumor suppressor associated with uveal melanoma, mesothelioma, cutaneous melanoma, renal cell carcinoma, and cutaneous BAP1-inactivated melanocytic tumors. However, the full spectrum of tumors associated with the syndrome is yet to be determined. Improved understanding of the BAP1-TPDS is crucial for appropriate clinical management of BAP1 germline variant carriers and their families, including genetic counseling and surveillance for new tumors. METHODS: We collated germline variant status, tumor diagnoses, and information on BAP1 immunohistochemistry or loss of somatic heterozygosity on 106 published and 75 unpublished BAP1 germline variant-positive families worldwide to better characterize the genotypes and phenotypes associated with the BAP1-TPDS. Tumor spectrum and ages of onset were compared between missense and null variants. All statistical tests were two-sided. RESULTS: The 181 families carried 140 unique BAP1 germline variants. The collated data confirmed the core tumor spectrum associated with the BAP1-TPDS and showed that some families carrying missense variants can exhibit this phenotype. A variety of noncore BAP1-TPDS -associated tumors were found in families of variant carriers. Median ages of onset of core tumor types were lower in null than missense variant carriers for all tumors combined (P

Recent advances in genomics have improved the molecular classification of cutaneous melanocytic tumors. Among them, deep penetrating nevi (DPN) and plexiform nevi have been linked to joint activation of the MAP kinase and dysregulation of the β-catenin pathways. Immunohistochemical studies have confirmed cytoplasmic and nuclear expression of β-catenin and its downstream effector cyclin D1 in these tumors. We assessed nuclear β-catenin immunohistochemical expression in a large group of DPN as well as in the four most frequent differential diagnoses of DPN: "blue" melanocytic tumors, Spitz tumors, nevoid and SSM melanomas, and pigmented epithelioid melanocytomas (PEM). Nuclear β-catenin expression was positive in 98/100 DPN and 2/16 of melanomas (one SSM and one nevoid melanoma with a plexiform clone) and was negative in all 30 Spitz, 26 blue, and 6 PEM lesions. In 41% DPN, β-catenin expression was positive in more than 30% nuclei. No differences were observed in cytoplasmic and nuclear cyclin D1 expression between these tumor groups, suggesting alternate, β-catenin-independent, activation pathways. We have subsequently studied nuclear β-catenin expression in a set of 13 tumors with an ambiguous diagnosis, for which DPN was part of the differential diagnosis. The three out of four patients showing canonical DPN mutation profiles were the only β-catenin-positive cases. We conclude that nuclear β-catenin expression, independently from CCND1 expression, in a dermal melanocytic tumor is an argument for its classification as DPN. In ambiguous cases and in early combined DPN lesions, this antibody can be helpful as a screening tool. β-Catenin is also potentially expressed in a subset of malignant melanomas with CTNNB1 mutations.

Dysregulation of the phosphatidylinositol 3-kinase (PI3K) pathway is frequent in advanced follicular (FTC) and poorly differentiated thyroid (PDTC) carcinomas and has been implicated in oncogenesis and tumor progression. This study investigated the efficacy and safety of buparlisib, a pan-PI3K inhibitor in radioiodine refractory FTC and PDTC.The primary endpoint of this open-label, multicenter, phase 2 pilot study was progression-free survival (PFS) at 6 months. The sample size was determined considering that a PFS ≤50% at 6 months would denote an absence of benefits (null hypothesis). Secondary endpoints were objective response rate, PFS at 12 months, overall survival at 6 and 12 months, and safety based on the frequency and severity of adverse events (AEs).Forty-three patients (19M/24 F; median age: 67 years) with metastatic, radioiodine refractory, progressive disease received buparlisib, 100 mg, daily. Histology was PDTC in 25 (58%), FTC in 17 (40%), and Hürthle cell carcinoma in 1 (2%). RAS mutation was found in 44% (12/27) and activation of the PI3K pathway in 35% (8/23) of tested tumors. The probability of PFS was 41.7% [95% confidence interval (CI) 7.7-55.5] at 6 months and 20.9% [CI 0-35.7] at 12 months, lower than the 50% expected PFS. At 6 months, 25.6% patients had stable disease, 48.8% were progressive and 25.6% had stopped treatment due to AE. The response to therapy was not influenced by age, sex, histology, or genetic alterations. The overall survivals at 6 and 12 months were 85.9% [CI 76-97] and 78.7 % [CI 67-92], respectively. The mean tumor growth rate decreased from 3.78 mm/month [CI 2.61-4.95] before treatment to 0.8 mm/month [CI -0.2-1.88] during treatment (p 0.02). Severe grade 3-4 AEs occurred in 27 patients (63%), including hepatitis (25%), hyperglycemia (21%), mood disorders (12%), and skin toxicity (12%), with favorable outcome after temporary or permanent treatment discontinuation or dose reduction.Buparlisib did not result in significant efficacy in advanced FTC and PDTC. However, the decrease in tumor growth rate may suggest incomplete inhibition of oncogenic pathways and/or escape mechanisms. This should lead to evaluate combined therapy associating inhibitors of both the PI3K and mitogen-activated protein kinase pathways.

Primary malignant melanoma of the esophagus is rare, accounting for less than 0.1–0.2% of all esophageal malignancies. It is associated with a poor outcome due to late detection and high metastatic potential. Here, we report a case of esophageal cancer, which was initially diagnosed as an adenocarcinoma and finally was confirmed as a primary malignant melanoma. This 75-year-old Caucasian male had a history of dysphagia and recent lingering abdominal pain. First biopsy showed a poorly-differentiated adenocarcinoma. He was then treated with neoadjuvant radiochemotherapy. Biopsies were repeated because of an incomplete tumor response, evaluated by endoscopic and imaging studies. The final diagnosis was a malignant melanoma. The patient has been treated with immune-checkpoint inhibitor, nivolumab, an anti-PD1 antibody.

// Xiaojun Jiang 1 , Daniel Pissaloux 1 , Christelle De La Fouchardiere 2 , Francoise Desseigne 2 , Qing Wang 1 , Valery Attignon 1 , Marie-Eve Fondrevelle 5 , Arnaud De La Fouchardiere 5 , Maurice Perol 2 , Philippe Cassier 2 , Christelle Seigne 3 , David Perol 3 , Isabelle Ray-Coquard 2 , Pierre Meeus 4 , Jerome Fayette 2 , Aude Flechon 2 , Axel Le Cesne 7 , Nicolas Penel 6 , Olivier Tredan 2 , Jean-Yves Blay 1, 2 1 Department of Translational Research, Centre Leon Berard, 69008 Lyon France 2 Department of Medical Oncology, Centre Leon Berard, 69008 Lyon France 3 Department of Clinical Research, Centre Leon Berard, 69008 Lyon France 4 Department of Surgery, Centre Leon Berard, 69008 Lyon France 5 Department of Pathobiology, Centre Leon Berard, 69008 Lyon France 6 Department of Medical Oncology, Centre Oscar Lambret, 59020 Lille France 7 Department of Medical Oncology, Gustave Roussy, 94805, Villejuif France Correspondence to: Xiaojun Jiang, e-mail: xiaojun.jiang@lyon.unicancer.fr Jean-Yves Blay, e-mail: jean-yves.blay@lyon.unicancer.fr Keywords: multi-kinase inhibitor, biomarker, regorafenib, chromosomal instability Received: May 06, 2015 Accepted: July 09, 2015 Published: July 21, 2015 ABSTRACT Validated predictive biomarkers for multi-tyrosine kinase inhibitors (MTKI) efficacy are lacking. We hypothesized that interindividual response variability is partially dependent on somatic DNA copy number alterations (SCNAs), particularly those of genes encoding the protein tyrosines targeted by MTKI (called target genes). Genomic alterations were investigated in MTKI responsive and non responsive patients with different histological subtypes included in the ProfiLER protocol (NCT 01774409). From March 2013 to August 2014, 58 patients with advanced cancer treated with one of 7 MTKIs were included in the ProfiLER trial and split into one discovery cohort ( n = 13), and 2 validation cohorts ( n = 12 and 33). An analysis of the copy number alterations of kinase-coding genes for each of 7 MTKIs was conducted. A prediction algorithm (SUMSCAN) based on the presence of specific gene gains (Tumor Target Charge, TTC) and losses (Tumor Target Losses, TTL) was conceived and validated in 2 independent validation cohorts. MTKI sensitive tumors present a characteristic SCNA profile including a global gain profile, and specific gains for target genes while MTKI resistant tumors present the opposite. SUMSCAN favorable patients achieved longer progression-free and overall survival. This work shows that the copy number sum of kinase-coding genes enables the prediction of response of cancer patients to MTKI, opening a novel paradigm for the treatment selection of these patients.

International audience; Dermatofibrosarcoma protuberans is underlined by recurrent collagen type I alpha 1 chain-platelet-derived growth factor B chain (COL1A1-PDGFB) fusions but ~ 4% of typical dermatofibrosarcoma protuberans remain negative for this translocation in routine molecular screening. We investigated a series of 21 cases not associated with the pathognomonic COL1A1-PDGFB fusion on routine fluorescence in situ hybridization (FISH) testing. All cases displayed morphological and clinical features consistent with the diagnosis of dermatofibrosarcoma protuberans. RNA-sequencing analysis was successful in 20 cases. The classical COL1A1-PDGFB fusion was present in 40% of cases (n = 8/20), and subsequently confirmed with a COL1A1 break-apart FISH probe in all but one case (n = 7/8). 55% of cases (n = 11/20) displayed novel PDGFD rearrangements; PDGFD being fused either to the 5' part of COL6A3 (2q37.3) (n = 9/11) or EMILIN2 (18p11) (n = 2/11). All rearrangements led to in-frame fusion transcripts and were confirmed at genomic level by FISH and/or array-comparative genomic hybridization. PDGFD-rearranged dermatofibrosarcoma protuberans presented clinical outcomes similar to typical dermatofibrosarcoma protuberans. Notably, the two EMILIN2-PDGFD cases displayed fibrosarcomatous transformation and homozygous deletions of CDKN2A at genomic level. We report the first recurrent molecular variant of dermatofibrosarcoma protuberans involving PDGFD, which functionally mimic bona fide COL1A1-PDGFB fusions, leading presumably to a similar autocrine loop-stimulating PDGFRB. This study also emphasizes that COL1A1-PDGFB fusions can be cytogenetically cryptic on FISH testing in a subset of cases, thereby representing a diagnostic pitfall that pathologists should be aware of.

Uveal melanoma (UM) is the most common primary tumor in the adult, and disseminates to the liver in half of patients. A 15-gene expression profile prognostic assay allows to determine the likelihood of metastasis in patients using their ocular tumor DNA, but a cure still remains to be discovered. The serotonin receptor 2B represents the discriminant gene of this molecular signature with the greatest impact on the prognosis of UM. However, its contribution to the metastatic potential of UM remains unexplored. The purpose of this study was to investigate the effects of a selective serotonin receptor 2B antagonist on cellular and molecular behaviours of UM cells. UM cell lines expressing high level of serotonin receptor 2B proteins were selected by Western blotting. The selective serotonin receptor 2B antagonist PRX-08066 was evaluated for its impact on UM cells using viability assays, phosphorylated histone H3 immunostainings, clonogenic assays, migration assays, invasion assays and membrane-based protein kinase phosphorylation antibody arrays. The pharmacological inhibition of the serotonin receptor 2B reduced the viability of UM cells and the population in mitosis, and impaired their clonogenicity and potential of migration. It also decreased the phosphorylation of kinases from signaling pathways classically activated by the serotonin receptor 2B, as well as kinases β-catenin, Proline-rich tyrosine kinase 2, and Signal transducer and activator of transcription 5. Our findings support a role for the serotonin receptor 2B in the proliferation and migration of UM cells, through activation of many signaling pathways such as WNT, Focal adhesion kinase and Janus kinase/STAT.

Deep penetrating nevus (DPN) is characterized by enlarged, pigmented melanocytes that extend through the dermis. DPN can be difficult to distinguish from melanoma but rarely displays aggressive biological behavior. Here, we identify a combination of mutations of the β-catenin and mitogen-activated protein kinase pathways as characteristic of DPN. Mutations of the β-catenin pathway change the phenotype of a common nevus with BRAF mutation into that of DPN, with increased pigmentation, cell volume and nuclear cyclin D1 levels. Our results suggest that constitutive β-catenin pathway activation promotes tumorigenesis by overriding dependencies on the microenvironment that constrain proliferation of common nevi. In melanoma that arose from DPN we find additional oncogenic alterations. We identify DPN as an intermediate stage in the step-wise progression from nevus to melanoma. In summary, we delineate specific genetic alterations and their sequential order, information that can assist in the diagnostic classification and grading of these distinctive neoplasms., Deep penetrating nevi (DPN) are unusual melanocytic neoplasms with unknown genetic drivers. Here the authors show that majority of DPN harbor activating mutations in the β-catenin and the MAP-kinase pathways; this characteristic can help in the classification and grading of these distinctive neoplasms.

Necrotizing Infundibular Crystalline Folliculitis (NICF) is rare entity of unknown pathogenesis presenting as follicular crystalline papules arising in seborrheic areas. We report 2 cases of NICF in patients under targeted therapy for metastatic adenocarcinoma. In one case, the lesions reappeared cyclically every 3 weeks after each injection and in the other case, lesions persisted until disruption of the continuous oral therapy. Punch-biopsies demonstrated folliculitis with a plugging crystalline material associated with either bacteria or yeast. These are the first descriptions of drug-induced NICF.

International audience; PURPOSE. Development of liver metastasis remains the most common cause of mortality in uveal melanoma (UM). A few cell lines cultured from primary UM tumors have been used widely to investigate the pathobiology of UM. However, the translation of basic knowledge to the clinic for the treatment of the metastatic disease has remained incremental at best. In this study, we examined whether the properties of UM cell lines at various passages were similar to their corresponding primary tumors. METHODS. Gene expression profiling by microarray was performed on UM primary tumors and derived cell lines cultured at varying passages. Expression of UM protein markers was monitored by immunohistochemical analyses and Western blotting. The in vivo tumorigenic properties of UM cultures were evaluated using athymic nude mice. RESULTS. Cell passaging severely reduced the expression of genes encoding markers typical of UM, including those of the prognostic gene signature. Marked differences between gene expression profiles of primary tumors and cell lines could be linked to the infiltrating immune and stromal cells in situ. In addition, the tumorigenic properties of UM cell lines also increased with cell passaging in culture as evaluated by their subcutaneous injection into athymic mice. CONCLUSIONS. Together, these findings demonstrate that the short-term UM primary cultures exhibit molecular features that resemble the respective surgical material and, thus, represent the best model for in vitro-assessed cancer treatments.