TNF and melanoma: Interleukin-1-α (IL-1α) and interleukin-1-β (IL-1β) upregulate MC1R mRNA in normal human melanocytes [23], while TNF-α [29] and TGF-β [30], that potently repress melanogenesis in melanoma cells, moderately downregulate MC1R expression in normal melanocytes [23] and mouse melanoma cells [31].