α-MSH and other neurohormones, as well as neuropeptides including substance P, calcitonin gene-related peptide (CGRP), enkephalin, and β-endorphin, have all been implicated as potential factors in the development, growth, invasion, and dissemination of melanoma in a variety of in vitro and in vivo studies (31). This evidence concerns the gene TAC1 and melanoma.