TYR and metastatic melanoma: In this context, an interesting question to answer is whether the SK-MEL-1 cells exposed to melatonin are more sensitive to cytotoxic properties of conventional antitumor agents since overexpression of tyrosinase has been reported to sensitize human melanoma cells to dacarbazine, an alkylating agent that is used in the therapy against metastatic malignant melanoma usually in combination with other antineoplastic agents [63].