BRAF and skin neoplasm: Approximately 50% of BRAF-mutant melanomas initially respond to vemurafenib alone as first-line therapy.4 MPAS in skin cancer (melanoma) tissues that were analyzed from TCGA varied widely (−1.5 to 2) and independently of mutational status (Fig. 2a), suggesting that dependence on MAPK signaling in these tumors is highly variable even within the BRAF-mutant population.