Malignant melanoma (MM) is the more aggressive form of skin cancer with a mortality rate in Argentina 1997-2001 = 1.1/100 000 in men and 0.6 in women. BRAF proto-oncogene is focus of intense research; its mutation is one of the main tumor promoters and occurs in approximately 50% of MM. Several drugs with clinical activity on BRAF mutations have been approved. The aim of the study is to evaluate the mutational status of BRAF (exon 15) in cutaneous MM biopsies and its relationship with histopathological characteristics. We carried out an observational, retrospective study of samples fixed in formaldehyde and paraffin embedded; reviewing age, sex, diagnosis, histopathological data, tumor size and percentage, viability for molecular analysis and melanin presence. We evaluated BRAF mutations with PCR/Sanger sequencing. For statistics we used Student's t test, Chi square, Wilcoxon and Fisher's exact test. We were able to purify and sequence 76% (38/49) samples, 13/38 (34%) from women and 25/38 (66%) from men, the median age being 70 years. Most frequent location: thorax 14/35 (40%). Histological type: Superficial spreading 18/38 (47%). Clark's levels, 11/38 (29%): I-II and 27/38 (71%): III, IV and V. Breslow's median: 1.6 mm. Radial growth phase 11/38 (29%) and 27/38 (71%) vertical. Presented mutations 16/38 (42%). As reported by other authors, no association was found between the mutational state of exon 15 and clinical or histopathological parameters.

Lung carcinoma is the main cause of cancer death worldwide. Adenocarcinoma molecular biomarkers have been discovered, and targeted therapies have been developed with encouraging results. The epidermal growth factor receptor gene is one of these biomarkers. Exons 18 to 21 should be studied in patients with advanced adenocarcinoma, who are candidates for treatment with tyrosine kinase inhibitors. The objective was to compare the performance of the determination in large and small samples in daily practice conditions, trying to adjust to published consensus guidelines. A retrospective observational study of 141 cases was carried out, with exons 19 and 21 sequencing. Sample size (small vs. large), including number of satisfactory polymerase chain reaction (PCR), sequencing, deletions, and mutations, were evaluated. In small biopsies, sample type, fragment number, and percentage of tumor per sample were analyzed. The results shown 114/141 (80.8) cases that met selection criteria; 60/114 (53%) were large (surgical) and 54/114 (47%) were small samples (19/54 endoscopic, 17/54 fine needle aspiration clots, 4/54 lymph nodes, 14/54 core and other). All large samples were satisfactory PCR, 56/60 (93%) satisfactory sequencing, and 12/56 (21%) had deletions in exon 19. Small samples were satisfactory PCRs in 50/54 (93%) cases, and satisfactory sequencing in 35/50 (65%), 8/35 (23%) showed alterations in exon 19, and 1/35 (3%) in exon 21. In conclusion, the proportion of samples unfit for the study of the epidermal growth factor receptor gene mutational status increased from 7% in large samples to 35% in small ones. Nineteen small samples were inconclusive, with cell blocks predominating, 10/19 (53%).

The prevalence of relevant oncogenic drivers in lung adenocarcinoma varies in our region and data on clinical outcomes is scarce. The objective of the study was to describe the prevalence of KRAS, BRAF and EGFR mutations and ALK translocations in patients with advanced lung adenocarcinoma, and to depict the clinical outcome according to treatment strategies. Patients with adequate tumor biopsy sampling were included. KRAS, BRAF and EGFR mutations were studied by Sanger sequencing. ALK translocations were studied by fluorescent in situ hybridization (FISH) and immunohistochemistry (IH) with antibodies against ALK with clones D5F3 and 5A4. Informed consent was signed by 118 patients and 84 (72%) with complete molecular analysis were included. KRAS mutations were detected in 16 samples (19%), EGFR in 11 (13%), 9 of them conferring sensitivity to EGFR inhibitors, and BRAF mutations in 1 (1%). ALK translocations were detected in 3 samples (4%). Median follow-up was 42.4 [interquartile range (IQR): 27.0-64.2] months. Globally, median overall survival was 10.3 [IQR: 5.6-20.2] months. Median survival was 10.8 [IQR: 6.0-20.3] months in the group of patients without detectable molecular alteration, 9.6 [IQR: 3.7-16.1] months in KRAS mutant population (HR: 1.08; p = 0.82) and 32.5 [IQR: 19.6-38.4] months in patients with ALK translocations or sensitizing EGFR mutated tumors treated with tyrosine kinase inhibitors (HR: 0.27; p = 0.03). In conclusion, the prevalence of molecular alterations and outcomes in our population is similar to that reported in other studies in Western countries.