TAC1 and melanoma: Studies on cancer research also reported that both NK-1R and its preferred ligand (neurokinin 1, NK-1 aka substance P, SP) are overexpressed in a wide variety of malignancies, including leukemia, glioblastoma, astrocytoma, neuroblastoma, melanoma, breast, ovarian, prostate, lung, pancreas and thyroid cancer [12,13], with a role in different driving agents to resistance, such as angiogenesis, cancer cell proliferation, migration and metastasis [12,13,14,15,16].