MCAM and melanoma: By deducing from the knowledge we have gained about the tumorigenesis of other tumor cell lines (such as melanoma and breast, ovary, and prostate cancers) induced by huMETCAM/MUC18, huMETCAM/MUC18 may affect tumorigenesis through cross-talk with many signaling pathways that regulate the proliferation, survival, apoptosis, metabolism, and angiogenesis of tumor cells [14,16,18,23,29].