Slow repair of pyrimidine dimers at p53 mutation hotspots in skin cancer.

Ultraviolet light has been linked with the development of human skin cancers. Such cancers often exhibit mutations in the p53 tumor suppressor gene. Ligation-mediated polymerase chain reaction was used to analyze at nucleotide resolution the repair of cyclobutane pyrimidine dimers along the p53 gene in ultraviolet-irradiated human fibroblasts. Repair rates at individual nucleotides were highly variable and sequence-dependent. Slow repair was seen at seven of eight positions frequently mutated in skin cancer, suggesting that repair efficiency may strongly contribute to the mutation spectrum in a cancer-associated gene.