MCAM and melanoma: Using knowledge derived from tumorigenesis of other tumors [28] and functions of huMETCAM/MUC18 in endothelial cells and melanoma [3,4,15,29-31], huMETCAM/MUC18 expression may increase tumorigenesis by cross-talk with many signaling pathways that affect survival, proliferation, and angiogenesis of tumor cells [3,4].