Medulloblastoma (MB) is the most prevalent brain cancer in children. Four subgroups of MB have been identified; of these, Group 3 is the most metastatic. Its genetics and biology remain less clear than the other groups, and it has a poor prognosis and few effective treatments available. Tumor hypoxia and the resulting metabolism are known to be important in the growth and survival of tumors but, to date, have been only minimally explored in MB. Here we show that Group 3 MB tumors do not depend on the canonical transcription factor hypoxia-inducible factor-1α (HIF-1α) to mount an adaptive response to hypoxia. We discovered that HIF-1α is rendered inactive either through post-translational methylation, preventing its nuclear localization specifically in Group 3 MB, or by a low expression that prevents modulation of HIF-target genes. Strikingly, we found that HIF-2 takes over the role of HIF-1 in the nucleus and promotes the activation of hypoxia-dependent anabolic pathways. The exclusion of HIF-1 from the nucleus in Group 3 MB cells enhances the reliance on HIF-2's transcriptional role, making it a viable target for potential anticancer strategies. By combining pharmacological inhibition of HIF-2α with the use of metformin, a mitochondrial complex I inhibitor to block respiration, we effectively induced Group 3 MB cell death, surpassing the effectiveness observed in Non-Group 3 MB cells. Overall, the unique dependence of MB cells, but not normal cells, on HIF-2-mediated anabolic metabolism presents an appealing therapeutic opportunity for treating Group 3 MB patients with minimal toxicity.

AVI file - 5901K, Video 5 (related to Fig. 2G) is a time-lapse recording of a mononucleate a3-/- cell that formed a tetranucleate cell after two rounds of abortive mitosis.

<p>AVI file - 875K, Video 2 (related to Fig. 2D) shows the delayed abscission of an a3-/- cell that remained connected by an intracellular bridge for up to 8 h 45 min before separating.</p>

AVI file - 2112K, Video 4 (related to Fig. 2F) illustrates the failed abscission of a mononucleated a3-/- cell that exited mitosis as a binucleated cell after 18 attempts at cleavage furrow formation. Note that this cell developed ectopic furrows, which led to the formation of anuclear fragments that fused back to the cell.

Among sarcomas, MDM2 amplification is usually a molecular hallmark of well-differentiated liposarcoma and dedifferentiated liposarcoma (DDLPS) and occasionally a secondary genetic anomaly in other sarcomas. Histological evaluation and FISH analysis showing MDM2 amplification led to the diagnosis of DDLPS for a tumor located on the left arm of a 71-year-old patient. The patient was treated by adjuvant radiotherapy (RT) but the tumor recurred soon after. Array-comparative genomic hybridization and targeted RNA/DNA sequencing of the primary tumor and of four recurrences were done. Strikingly, the MDM2 amplification observed in the primary tumor had vanished in the recurrences. In contrast, other rearrangements, such as amplification of the genes TRIO and TERT as well as TRIO::TERT fusion were detected retrospectively in the primary tumor and in all the recurrences. The transitory nature of the MDM2 amplification raised the hypothesis that RT was active on cells that contained MDM2 amplification but not on other tumor cells with only the TERT and TRIO alterations. In contrast to MDM2 amplification, the TRIO::TERT amplified fusion was stable over time. The detection of this fusion was crucial in the analysis of the diagnostically challenging last tumor; it allowed to determine that it was a fourth recurrence, instead of a new independent tumor. It also suggested the diagnosis undifferentiated pleomorphic sarcoma rather than DDLPS. The TRIO::TERT fusion is not well explored. The current study shows that its role in sarcomas, with or without MDM2 amplification, should be more extensively researched.

AVI file - 2696K, Video 3 (related to Fig. 2E) is a time-lapse recording of four pairs of a3-/- cells that entered mitosis synchronously, likely bridged sister cells. Pairs of cells that entered mitosis synchronously are outlined in color in the first frame, and then marked with dots in the next frame to help visualize their progression in mitosis.

Uveal melanoma (UM) is the most common intraocular tumour in adults, with dismal prognosis once metastases develop, since therapeutic options for the metastatic disease are ineffective. Over the past decade, novel cancer therapies based on immunotherapy have changed the landscape of treatment of different forms of cancer leading to many hopes of improvement in patient overall survival (OS). VISTA, LAG-3 and PRAME are novel promising targets of immunotherapy that have recently gained attention in different solid tumours, but whose relevance in UM remained to be comprehensively evaluated until now. Here, we studied the protein expression of VISTA, LAG-3 and PRAME using immunohistochemistry in representative whole tissue sections from primary UM cases in a cohort of 30 patients from a single centre (Nice University Hospital, Nice, France). The expression of each of these markers was correlated with different clinical and pathological parameters, including onset of metastases and OS. We demonstrated the protein expression of VISTA and LAG-3 in small lymphocytes infiltrating the tumour, while no expression of the proteins was detected in UM cells. For PRAME, nuclear expression was observed in UM cells, but no expression in tumour infiltrating immune cells was identified. Increased levels of VISTA expression in tumour infiltrating lymphocytes (TILs) were associated with nuclear BAP1 expression and better prognosis. Higher levels of LAG-3 in TILs were associated with higher levels of CD8-positive TILs. PRAME nuclear positivity in melanoma cells was associated with epithelioid cell dominant (>90%) UM histological subtype, higher mitotic numbers and a higher percentage of chromosome 8q gain. This study proposes VISTA as a novel relevant immune checkpoint molecule in primary UM and contributes to confirm LAG-3 and PRAME as potentially important immunotherapy targets in the treatment of UM patients, helping to expand the number of immunotherapy candidate molecules that are relevant to modulate in this aggressive cancer.

Merkel cell carcinoma (MCC) is a rare and aggressive cutaneous neuroendocrine cancer. Management of advanced MCC is mainly based on immune-checkpoint inhibitors. The high failure rate warrants an investigation of new therapeutic targets. The recent identification of BRCA1 or BRCA2 (BRCA1/2) mutations in some MCC raises the issue of the use of poly-(ADP-Ribose)-polymerase inhibitors in selected advanced cases. The main objective of our study is to determine the accurate frequency of BRCA1/2 pathogenic variants. We studied a series of 30 MCC and performed a meta-analysis of BRCA1/2 variants of published cases in the literature. In our series, we detected only one BRCA2 pathogenic variant. The low frequency of BRCA1/2 pathogenic variants in our series of MCC (3%) was confirmed by the meta-analysis of BRCA1/2 variants in the literature. Among the 915 MCC from 13 published series studied for molecular alterations of BRCA1/2, only 12 BRCA1/2 pathogenic mutations were identified (1-2% of MCC), whereas many other BRCA1/2 variants were variants of unknown significance or benign. BRCA1/2 pathogenic variants are uncommon in MCC. However, in BRCA-mutated MCC, poly-(ADP-Ribose)-polymerase inhibitors might be a valuable therapeutic option requiring validation by clinical trials.

Onychomatricoma (OM), an uncommon benign fibroepithelial neoplasm of the nail unit, is sometimes diagnostically challenging for clinicians and pathologists. OM consistently expresses CD34, but no specific immunohistohemical markers or recurrent genetic alterations have been identified to date. Recent studies have suggested that Wnt signalling is a key molecular characteristic of OM.

<p>AVI file - 645K, Video 6 (related to Fig. 6A) is a time-lapse recording showing that the ATG5-depleted A549 cells formed numerous ectopic furrows in addition to a wider-than-normal equatorial cleavage furrow.</p>

<p>AVI file - 718K, Video 1 (related to Fig. 2A) is a time-lapse recording showing the normal cell division of control wild-type (WT) cells. In the last frame, the daughter WT cells are outlined in white to help visualize their successful division.</p>

Supplementary Data from Imatinib Mesylate as a Preoperative Therapy in Dermatofibrosarcoma: Results of a Multicenter Phase II Study on 25 Patients

First described in 2014, renal cell carcinoma (RCC) with TFEB amplification (6p21) is a rare molecular subgroup whose diagnosis is challenging. The prognosis and therapeutic implications remain unclear.

Local or metastatic relapse following surgery, radiotherapy, and cisplatin is the leading cause of death in patients with head and neck squamous cell carcinoma (HNSCC). Our study shows overexpression of c-MET and AXL in HNSCC cells and patients resistant to radiotherapy and cisplatin. We demonstrate that cabozantinib, an inhibitor of vascular endothelial growth factor receptor (VEGFR), c-MET, and AXL, decreases migration, invasion, and proliferation and induces mitotic catastrophe and apoptotic cell death of naive and radiotherapy- and cisplatin-resistant HNSCC cells. Cabozantinib inhibits the growth and metastatic spread of experimental HNSCC in zebrafish and the growth of experimental HNSCC in mice by blocking tumor cell proliferation and angiogenesis. The efficacy of cabozantinib is also confirmed on viable sections of surgically removed specimens of human HNSCC and on a patient who relapses after five lines of treatment. These results suggest that cabozantinib is relevant for the treatment of patients with HNSCC after relapse under radiotherapy and cisplatin.

Most available molecular data on pancreatic acinar cell carcinoma (PACC) are provided by studies of adult cases. BRAF, RAF1, or RET rearrangements have been described in approximately 30% of cases. To the best of our knowledge, only seven cases with molecular data have been reported in pediatric PACC. We report here the comprehensive study of a pancreatic-type ACC from a 6-year-old patient. We detected an AGAP3::BRAF fusion. This result showing a BRAF rearrangement demonstrates a molecular link between adult and pediatric PACC. Moreover, it identifies AGAP3, a gene located at 7q36.1 that encodes a major component of the N-methyl-d-aspartate (NMDA) receptor signaling complex, as a partner gene of BRAF. The variability of BRAF partners is consistent with a driver role of BRAF alterations in PACC. The identification of such alterations is noteworthy for considering the use of MEK inhibitors in metastatic cases. We did not detect associated genomic instability. The better outcome of pediatric cases might be related to their stable genomic background.

Les léiomyosarcomes cutanés (cLMS) sont des tumeurs malignes de différenciation musculaire lisse et de topographie superficielle, dermique ou hypodermique. Du fait de leur rareté, le pronostic des cLMS est encore débattu. À ce jour, il n'existe aucune étude moléculaire somatique portant sur les cLMS. L'objectif principal de notre étude était de réaliser la plus grande collection française de données cliniques et histologiques de lcLMS et d'étudier les facteurs associés à la survie globale (SG) et sans récidive (SSR). L'objectif secondaire était d'analyser ces tumeurs sur le plan moléculaire. Il s'agit d'une étude rétrospective menée de janvier 2000 à juin 2019, multicentrique issue de 4 centres experts de dermatologie (Nice, Montpellier, Lyon, Nîmes). Les caractéristiques démographiques et clinico-histologiques et les données de survie ont été collectées. SG et SSR ont été analysées selon la méthode de Kaplan-Meier. Les analyses moléculaires suivantes ont été réalisées : analyse quantitative pan-génomique et séquençage de nouvelle génération ciblé à partir d'ADN et d'ARN extraits des tissus tumoraux. Un total de 79 cLMS ont été inclus, dont 57 (72 %) d'hommes ; l'âge médian au diagnostic était de 70 ans (57–79 ans). La durée médiane de suivi était de 39 mois. Les taux estimés de SG et SSP à 24 mois étaient respectivement de 92 % et 77 %. Parmi les facteurs pronostiques, un grade histopronostique intermédiaire ou élevé selon la FNCLCC (grade II-III) était significativement associé à la survenue de récidives locales ou métastatiques (HR 4,8 ; 95 %IC [1,6–14,6] ; p = 0,01). Les localisations des métastases étaient osseuses (n = 3), cutanées (n = 2), coliques (n = 1), lymphatiques (n = 1) et hépatiques (n = 1). En cas de récidive (n = 9/42), les marges de résection cliniques étaient significativement moins larges (1,06 vs 1,80 cm, p = 0,03). Onze cas ont été étudiés au niveau moléculaire avec identification de trois types de profils : sans aucune anomalie quantitative (n = 4), une seule anomalie quantitative (n = 3) et profils complexes avec plus de 10 anomalies quantitatives (n = 4). Les gènes les plus fréquemment altérés étaient RB1, TP53 et MYOCD. Deux cas présentaient des mutations ponctuelles du gène TP53. Le pronostic des cLMS est variable avec un risque non négligeable de récidive locale ou à distance qui est particulièrement associé à un grade histopronostique intermédiaire ou élevé (II-III). Nos résultats suggèrent que des marges de résection à 2 cm et un suivi à long terme doivent être recommandés dans ces situations. De plus, nous avons identifié un sous-groupe de cLMS avec profil moléculaire « agressif » dont l'association éventuelle avec une évolution plus péjorative nécessite une analyse prospective.

Dermatofibrosarcoma protuberans (DFSP) is a soft-tissue sarcoma characterized by a high risk of local infiltration. The identification of the COL1A1-PDGFB t(17;22) translocation activating the PDGF pathway led to the use of imatinib in unresectable DFSP, with a response rate of 36-80%. Pazopanib is a multitarget tyrosine kinase inhibitor approved for soft-tissue sarcomas. We conducted a phase II study of patients with unresectable DFSP to evaluate the efficacy and safety of pazopanib. Patients received 800 mg of pazopanib daily. The primary endpoint was the objective response rate defined as the reduction of the largest diameter of the tumor by >= 30% at 6 months or at surgery. A total of 23 patients, including one pretreated with imatinib, were enrolled. With a median follow-up of 6.2 months (interquartile range = 5.6-7.8 months), five patients (22%, 95% confidence interval = 7-22%) had a partial response to pazopanib. The best objective response rate was 30% (95% confidence interval = 13-53%) using Response Evaluation Criteria in Solid Tumors. One patient with metastatic DFSP previously treated with imatinib died after 2.4 months. Nine patients (39%) discontinued the treatment owing to adverse events. Pharmacodynamics analyses of tumor samples were conducted: the enrichment of EGF and the EGFR-associated gene panel was associated with resistance, suggesting that EGFR-targeted therapies could be a therapeutic option to explore in DFSP.

The accurate diagnosis of Xp11-translocation renal cell carcinoma (RCC) in adults is challenging. TFE3 (located on chromosome X) fuses with a partner gene generally located on another chromosome. In rare cases TFE3 may fuse with a neighboring gene: RBM10. Because TFE3 false-positive immunostaining is a common pitfall in many laboratories, demonstration of the chromosomal rearrangement is required in order to ascertain the diagnosis. Fluorescence in situ hybridization (FISH)-that has been considered as the gold standard method-reaches its limits for detecting small Xp11 paracentric inversions. We performed a comprehensive clinical, histological and genomic study of six novel cases of RCC with RBM10-TFE3 fusion. Using FISH, TFE3 rearrangement was equivocal in one case and negative in others. RBM10-TFE3 fusion was discovered using targeted RNA sequencing (RNASeq). As all the previously reported cases (mean age: 50), the six patients were adults (mean age: 42), suggesting an epidemiologic difference between RBM10-TFE3 RCC and tumors harboring some other partner genes, such as ASPSCR1 that rather occur in children. Array-comparative genomic hybridization showed several alterations, notably a gain of 17q in four cases with papillary features and loss of 3p in one case with clear cells. Our study demonstrates that, though rare among adult cases of RCC, RBM10-TFE3 fusion is not exceptional and warrants appropriate molecular detection. Notably, it would be worthy to systemically investigate by RNASeq challenging RCC with type-2 papillary features and 17q gain.

Society for Publication of Acta Dermato-Venereologica Superficial CD34+ fibroblastic tumour (SCFT) is an uncommon low-grade mesenchymal tumour of intermediate (borderline) malignancy. It occurs in middle-aged adults, with a slight male predilection, most frequently on the lower limbs, particularly the thighs (1–8). To the best of our knowledge, there has been no report of this tumour occurring in the subungual or periungual region. We report here the first case of SCFT of subungual region of the finger with a misleading clinical feature. Immunohistochemical features and RNA sequencing analysis using a panel dedicated to sarcomas ruled out more aggressive neoplasms, such dermatofibrosarcoma protuberans (DFSP).