How do these defective DNA repair genes relate to developing skin cancer?
Dr. Kraemer: Ultraviolet (UV) radiation penetrates the skin and damages the DNA. The DNA repair genes may repair the damaged cells, the damaged cells may die or, in other cases, the cells try to continue working and replicate the DNA, but because of the damage, there is a mutation introduced that can lead to cancers. So XP patients have a defect in their DNA repair system that leads to the 1,000-fold increase in skin cancer. We’ve been studying XP patients here at NIH, and we have found there are a number of different DNA repair genes that are responsible for this disorder. These findings mean that those genes are protecting the people who don’t have XP from getting skin cancers. What are some of the promising areas of research in nonmelanoma skin cancer prevention? Dr. DiGiovanna: Isotretinoin (Accutane), a derivative of vitamin A, has been studied as an agent to prevent cancers in patients at high risk, and it has been effective in studies of XP patients, who develop large numbers of
