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.

BRAF inhibitors have demonstrated improvement of overall survival in patients with metastatic melanoma and BRAFV600 mutations. In order to evaluate BRAF tumor heterogeneity between primary and metastatic site, we have evaluated the performance of immunohistochemistry (IHC) with an anti-BRAFV600E antibody in both localization by comparison with high resolution melting analysis followed by Sanger sequencing in a parallel blinded study. A total of 230 samples distributed as primary melanoma (n = 88) and different types of metastatic samples (n = 142) were studied in 99 patients with advanced or metastatic melanoma (stage III or IV). The prevalence of each BRAF mutation was c.1799T>A, BRAFV600E (45.2%), c.1799_1800TG>AA, BRAFV600E2 (3.0%), c.1798_1799GT>AA, BRAFV600K (3.0%), c.1801 A>G, BRAFK601E (1.3%), c.1789_1790CT>TC, BRAFL597S (0.4%), c.1780G>A, BRAFD594N (0.9%) respectively. IHC was positive in 109/112 samples harboring BRAFV600E/E2 mutations and negative in other cases. The cytoplasmic staining was either strongly positive in tumor cells of BRAFV600E mutated cases. It appeared strong brown, different from the vesicular grey cytoplasmic pigmentation of melanophages. Concordance between the two techniques was 96.4%. Sensitivity of IHC for detecting the BRAFV600E/E2 mutations was 97.3%, while specificity was 100%. Both our IHC and molecular study demonstrated homogeneity between primary and metastatic sites for BRAF status in melanoma. This study also provides evidence that IHC may be a cost-effective first-line method for BRAFV600E detection. Thereafter, molecular techniques should be used in negative, ambiguous or non-contributive cases.

Our results suggest that, in contrast to FOXL2 mutations in A-GCT, DICER1 mutations in SLCT might be more useful for prognosis than for diagnosis. However, study of a larger cohort of patients is necessary to establish this. Identification of genetic alterations in SCST offers promising therapeutic options.

Background: In 2013, the French National Cancer Institute initiated the AcSé program to provide patients with secure access to targeted therapies outside of their marketed approvals. Efficacy and safety was then assessed using a two-stage Simon phase II trial design. When the study design was designed, crizotinib was approved only as monotherapy for adults with anaplastic lymphoma kinase plus non-small-cell lung cancers (NSCLC).Patients and methods: Advanced NSCLC patients with c-MET 6 copies, c-MET-mutated, or ROS-1-translocated tumours were enrolled in one of the three cohorts. Patients were treated with crizotinib 250 mg twice daily. Efficacy was assessed using the objective response rate (ORR) after two cycles of crizotinib as primary outcome. Secondary outcomes included disease control rate at four cycles, best ORR, progression-free survival, overall survival, and drug tolerance.Results: From August 2013 to March 2018, 5606 patients had their tumour tested for crizotinib targeted molecular alterations: 252 patients had c-MET 6 copies, 74 c-MET-mutation, and 78 ROS-1-translocated tumour. Finally, 25 patients in the c-MET 6 copies cohort, 28 in the c-MET-mutation cohort, and 37 in the ROS-1-translocation cohort were treated in the phase II trial. The ORR was 16% in the c-MET 6 copies cohort, 10.7% in the mutated, and 47.2% in the ROS-1 cohort. The best ORR during treatment was 32% in the c-MET-6 copies cohort, 36% in the c-MET-mutated, and 69.4% in the ROS-1-translocation cohort. Safety data were consistent with that previously reported.Conclusions: Crizotinib activity in patients with ROS1-translocated tumours was confirmed. In the c-MET-mutation and c-MET 6 copies cohorts, despite insufficient ORR after two cycles of crizotinib, there are signs of late response not sufficient to justify the development of crizotinib in this indication. The continued targeting of c-MET with innovative therapies appears justified.

Interstitial deletion 1q24q25 is a rare rearrangement associated with intellectual disability, growth retardation, abnormal extremities and facial dysmorphism. In this study, we describe the largest series reported to date, including 18 patients (4M/14F) aged from 2 days to 67 years and comprising two familial cases. The patients presented with a characteristic phenotype including mild to moderate intellectual disability (100%), intrauterine (92%) and postnatal (94%) growth retardation, microcephaly (77%), short hands and feet (83%), brachydactyly (70%), fifth finger clinodactyly (78%) and facial dysmorphism with a bulbous nose (72%), abnormal ears (67%) and micrognathia (56%). Other findings were abnormal palate (50%), single transverse palmar crease (53%), renal (38%), cardiac (38%), and genital (23%) malformations. The deletions were characterized by chromosome microarray. They were of different sizes (490 kb to 20.95 Mb) localized within chromosome bands 1q23.3-q31.2 (chr1:160797550-192912120, hg19). The 490 kb deletion is the smallest deletion reported to date associated with this phenotype. We delineated three regions that may contribute to the phenotype: a proximal one (chr1:164,501,003-167,022,133), associated with cardiac and renal anomalies, a distal one (chr1:178,514,910-181,269,712) and an intermediate 490 kb region (chr1:171970575-172460683, hg19), deleted in the most of the patients, and containing DNM3, MIR3120 and MIR214 that may play an important role in the phenotype. However, this genetic region seems complex with multiple regions giving rise to the same phenotype.