Melatonin and the active forms of vitamin D in prevention and treatment of skin cancer

Melatonin, in addition of its neuroendocrine functions as the regulator of circadian rhythm, is also recognized for its anticancer properties. It also exerts complex antioxidative, cell protective and DNA repair mechanisms acting as a protector against ultraviolet radiation (UVR)-induced cancerogenesis. Vitamin D is a product of photochemical transformation of 7-dehydrocholesterol induced by UVB. After enzymatic activations, it can regulate skin functions, which include induction of cell differentiation, photoprotective and anticancer activities. UVR is a major risk factor for skin cancer including melanoma, the deadliest skin cancer, as well as squamous and basal cell carcinomas (SCC and BCC) collectively classified as nonmelanoma skin cancers (NMSC). NMSC is the most commonly diagnosed skin cancer with the UVB being the main inducing factor. NMSC has an enormous economic burden on the health system of the US, as well as the whole world. In this special issue on “Melatonin and active forms of vitamin D in prevention and treatment of skin cancer” we will discuss the therapeutic and chemopreventive role of these compounds and its metabolites in melanoma and NMSC. The various mechanism of action will be analyzed, with considerations whether these compounds can also enhance the efficacy of established therapies in patients affected by melanoma or NMSC. Any original experimental research, review articles, and commentary articles on this and related topics are invited.