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 development. Skin pigmentation is traditionally regarded as an important protection against skin cancer. Yet, little is known about how skin pigmentation is modulating induction of DNA damage, which is the primary event in carcinogenesis. We applied a recently developed 32P-postlabeling technique to measure the effect of constitutional pigmentation on the formation of major ultraviolet-induced DNA damage in human skin in vivo. The induction of photoproducts showed a statistically significant negative correlation with erythemal response and skin pigmentation. Our results demonstrated that the constitutional pigmentation is efficiently guarding DNA against the formation of photoproducts. The difference in melanin content is likely to be one of the reasons for the observed interindividual variation in levels of DNA damage after the uniform exposure to ultraviolet B.