Melanoma develops as a result of several genetic alterations, with UV radiation often acting as a mutagenic risk factor. Deep knowledge of the molecular signaling pathways of different types of melanoma allows better characterization and provides tools for the development of therapies based on the intervention of signals promoted by these cascades. The latest World Health Organization classification acknowledged the specific genetic drivers leading to melanoma and classifies melanocytic lesions into nine distinct categories according to the associate cumulative sun damage (CSD), which correlates with the molecular alterations of tumors. The largest groups are melanomas associated with low-CSD or superficial spreading melanomas, characterized by frequent presentation of the BRAFV600 mutation. High-CSD melanomas include lentigo maligna type and desmoplastic melanomas, which often have a high mutation burden and can harbor NRAS, BRAFnon-V600E, or NF1 mutations. Non-CSD-associated melanomas encompass acral and mucosal melanomas that usually do not show BRAF, NRAS, or NF1 mutations (triple wild-type), but in a subset may have KIT or SF3B1 mutations. To improve survival, these driver alterations can be treated with targeted therapy achieving significant antitumor activity. In recent years, relevant improvement in the prognosis and survival of patients with melanoma has been achieved, since the introduction of BRAF/MEK tyrosine kinase inhibitors and immune checkpoint inhibitors. In this review, we describe the current knowledge of molecular pathways and discuss current and potential therapeutic targets in melanoma, focusing on their clinical relevance of development.

BACKGROUND: The role of human papillomavirus (HPV) in the pathogenesis of squamous cell carcinomas (SCCs) of the sinonasal tract and its clinicopathological implications were evaluated.METHODS: All SCCs of the sinonasal tract diagnosed in the Hospital Clinic of Barcelona from 1981 to 2006 were retrospectively evaluated (N = 60). Clinical and pathological data were reviewed. HPV infection was determined and typed by amplification of HPV DNA by polymerase chain reaction using the SPF‐10 primers. p16^INK4a expression was determined by immunohistochemistry. Overall and progression‐free survival for HPV‐positive and ‐negative patients was estimated by Kaplan‐Meier analysis and by the use of a multivariate Cox proportional hazards model.RESULTS: HPV DNA was detected in tumor tissue of 12 of 60 (20%) patients. HPV16 was identified in 11 tumors and HPV35 in 1. Immunohistochemistry for p16^INK4a stained all HPV‐positive and no HPV‐negative tumors (P < .001). No differences were observed in terms of site and histological grade or stage at presentation between HPV‐positive and ‐negative tumors. However, HPV‐positive patients had a significantly better 5‐year progression‐free survival (62%; 95% confidence interval [CI], 23%‐86% vs 20%; 95% CI, 9%‐34%; P = .0043, log‐rank test) and overall survival (80%; 95% CI, 20%‐96% vs 31%; 95% CI, 15%‐47%; P = .036, log‐rank test) than patients with HPV‐negative tumors. In multivariate analysis, HPV‐positive tumors were associated with improved progression‐free survival (hazard ratio, 0.21; 95% CI, 0.17‐0.98; P = .012).CONCLUSIONS: A subgroup of sinonasal SCCs is associated with HPV infection. These tumors have a significantly better prognosis. Cancer 2009. © 2009 American Cancer Society.

Mucins are glycoproteins normally synthesized by a variety of secretory epithelial cells. The aim of this study was to investigate the expression of mucins (MUC1, MUC2, MUC4, MUC5AC, MUCB, MUC6, MUC7) in mucoepidermoid carcinomas, the most frequent malignant tumor of salivary glands. Forty mucoepidermoid carcinomas and twenty-two normal salivary glands were studied for these mucins by immunohistochemistry from formalin-fixed and paraffin-embedded material. Normal salivary glands frequently expressed MUC1 and MUC4, mainly in ductal cells; MUC5B and MUC7 stained mucous and serous acini respectively of submandibular and minor salivary glands; and MUC5AC and MUC2 were poorly detected in excretory ducts. All mucoepidermoid carcinomas expressed MUC1, and 38/40 tumors expressed MUC4. Both membrane-bound mucins stained membranes and cytoplasm of all cell types (epidermoid, intermediate, mucous, clear and columnar). MUC5AC and MUC5B stained glandular differentiated cells in most tumors (29/40 and 33/40 cases, respectively). MUC6 was positive in 13/40 tumors, and both MUC2 and MUC7 in only 2/40 tumors. The high expression of MUC1 was related to high histologic grades, high recurrence and metastasis rates and a shorter disease-free interval (P < 0.05). Conversely, MUC4 high expression was mainly related to low-grade tumors, lower recurrence rates and a longer disease-free interval (P < 0.05). In conclusion, mucoepidermoid carcinomas of salivary glands usually express MUC1, MUC4, MUC5AC and MUC5B; less frequently MUC6; and rarely MUC2 and MUC7. This mucin expression pattern can be useful for diagnostic purposes. Therefore, MUC1 expression is related to tumor progression and worse prognosis, whereas MUC4 expression is related to a better prognosis.