BRAF and NRAS mutational status in clear cell sarcoma

9000 Background: Clear-cell-sarcoma (CCS) also known as melanoma of the soft parts (MSP) is a rare cancer of adolescents and young adults arising in the deep soft tissues. Several clinical and pathological data demonstrate features typical of melanoma (the propensity for lymph node metastasis, expression of melanoma markers:HMB45, S100. Conversely, deep location in the soft tissues and recurrent t(12;22) translocation coding for the fusion protein EWS-ATF1 are rather suggestive of soft tissue sarcoma (STM). Data comparing gene expression profiles of CCS, melanomas and STM showed that CCS clustered with melanoma rather than with STM. BRAF mutations are frequently found in cutaneous melanoma (40–60%) but are not found in distinct melanoma subtypes(mucosal or uveal). Upstream of BRAF, on the same MAP kinase pathway NRAS is also frequently mutated in melanoma, with a mutually exclusive spectrum of mutations for these two genes. Our objective was to evaluate the frequency of BRAF and NRAS mutations is CCS. Met...