Effect of constitutional pigmentation on ultraviolet B-induced DNA damage in fair-skinned people

Ultraviolet light has been implicated as a dominant factor in skin cancer d evelopment. Skin pigmentation is traditionally regarded as an important pro tection against skin cancer. Yet, little is known about how skin pigmentati on is modulating induction of DNA damage, which is the primary event in car cinogenesis. We applied a recently developed P-32-postlabeling technique to measure the effect of constitutional pigmentation on the formation of majo r ultraviolet-induced DNA damage in human skin in vivo. The induction of ph otoproducts showed a statistically significant negative correlation with er ythemal response and skin pigmentation. Our results demonstrated that the c onstitutional pigmentation is efficiently guarding DNA against the formatio n of photoproducts. The difference in melanin content is likely to be one o f the reasons for the observed interindividual variation in levels of DNA d amage after the uniform exposure to ultraviolet B.