Cutaneous melanoma is a significant cause of morbidity and mortality. 
Nicotinamide is a safe, widely available vitamin that reduces the immune 
suppressive effects of UV, enhances DNA repair in keratinocytes and has shown 
promise in the chemoprevention of non-melanoma skin cancer. Here, we report the 
effect of nicotinamide on DNA damage and repair in primary human melanocytes. 
Nicotinamide significantly enhanced the repair of oxidative DNA damage 
(8-oxo-7,8-dihydro-2'-deoxyguanosine) and cyclobutane pyrimidine dimers induced 
by UV exposure. It also enhanced the repair of 
8-oxo-7,8-dihydro-2'-deoxyguanosine induced by the culture conditions in 
unirradiated melanocytes. A significant increase in the percentage of 
melanocytes undergoing unscheduled but not scheduled DNA synthesis was observed, 
confirming that nicotinamide enhances DNA repair in human melanocytes. In 
summary, nicotinamide, by enhancing DNA repair in melanocytes, is a potential 
agent for the chemoprevention of cutaneous melanoma.