Exposure to ultraviolet B (UV-B) light was associated with an increased risk of basal cell carcinoma and squamous cell carcinoma skin cancers, but not melanoma, new research suggests.Researchers at the University of Texas M.D. Anderson Cancer Center in Houston also found that UV-B exposure can reduce the ability of cells to repair DNA damage.The study included 469 patients with both melanoma and non-melanoma skin cancers and 329 cancer-free people. Blood samples taken from study volunteers were exposed to UV-B radiation and analyzed 24 hours later for the number of breaks in cell structures called chromatids, an indirect marker of DNA repair.A high number of chromatid breaks in the blood samples exposed to UV-B was associated with a three-fold increased risk of basal cell and squamous cell carcinomas, but was not associated with an increased risk of melanoma, the researchers found. They also found that increased sensitivity to UV-B radiation may interact with other known risk factors -- such as hair and skin color, sunburn history, tanning ability, and freckling -- to increase the risk of basal cell and squamous cell carcinomas.The study appears in the Dec. 21 issue of the Journal of the National Cancer Institute.
