TSC2 and melanoma: The observation of a melanocyte-like phenotype was supported by the fact that shRNA-Tsc2 + Cdkn2a sphere cells that were differentiated in neural-crest differentiation medium showed similar positive staining for CATHEPSIN K, PMEL, MITF and MART-1 to the B16F1 melanoma cell line (Supplementary Fig. 5).