Prognostic biomarkers for survival in mucosal melanoma.

e21576 Background: Mucosal Melanoma is a rare subtype of melanoma with a more aggressive clinical course when compared to cutaneous melanoma. In cutaneous melanoma, the absence of pigmentation and presence of NRAS/KRAS mutations are known as biomarkers indicating an aggressive clinical course with significantly shorter overall survival times. Similar data for mucosal melanoma are currently missing. Here, we present real world outcome data in a large cohort of genotyped mucosal melanoma patients and assessed the prognostic relevance of pigmentation- and NRAS/KRAS mutation status. Methods: We correlated pathological reports and clinical data with overall survival of patients with mucosal melanoma. Furthermore, we performed clinically integrated molecular genotyping and analyzed real world treatment regimens for covariates associated with clinical outcome. For institutional data analysis, we ran a source query and only included patients with the diagnosis of mucosal melanoma, available genotyping data and comprehensive clinical information. As a population-based reference and to directly compare overall survival differences we first queried the National Cancer Institute’s Surveillance, Epidemiology and End Results (SEER) database. Pigmentation status was assessed by pathological review. Treatment regimens were identified by chart review. Results: We identified a cohort of 39 patients with mucosal melanoma where clinical and molecular data was available. Patients with amelanotic mucosal melanoma had a significantly shorter overall survival ( p = 0.003). In addition, the presence of a NRAS or KRAS mutation was significantly associated with poor overall survival (NRAS or KRAS p = 0.024). Therapeutic regimens were heterogeneous with a mean of 5 treatment lines per patient. Patients with low stage tumors who received immunotherapy had a significantly shorter overall survival (p < 0.001), although numbers were small. Conclusions: The absence of pigmentation and the presence of NRAS or KRAS mutations are poor prognostic indicators for survival in CM. Both biomarkers are have been described in MM. Currently, it is unknown if the same prognostic relevance for the lack of pigmentation and RAS mutations exists in MM. Here we analyzed a cohort of MM for outcome measures and determined that two known prognostic biomarkers for CM are in fact novel prognosticators for MM.