Melanoma and nonmelanoma skin cancer chemoprevention: A role for nicotinamide?

Ultraviolet radiation (UVR) causes DNA damage in melanocytes by producing photolesions such as cyclobutane pyrimidine dimers and 8-oxo-7-hydrodeoxyguanosine. The production of reactive oxygen species by UVR also induces inflammatory cytokines that, together with the inherent immunosuppressive properties of UVR, propagate carcinogenesis. Nicotinamide (Vitamin B3 ) enhances DNA repair, modulates the inflammatory environment produced by UVR, and reduces UV-induced immunosuppression. As nicotinamide reduces the incidence of actinic keratoses and nonmelanoma skin cancers in high-risk individuals and enhances repair of DNA damage in melanocytes, it is a promising agent for the chemoprevention of melanoma in high-risk populations.