Xeroderma pigmentosum: a glimpse into nucleotide excision repair, genetic instability, and cancer.

Xeroderma pigmentosum (XP) is a rare DNA repair disorder characterized by extreme sensitivity to sunlight and severe predisposition to UV-induced skin cancer. Seven genes, ranging from XPA to XPG, are defective in XP. These genes are important components of the nucleotide excision repair (NER) system, which removes DNA damage induced by solar radiation, thereby preventing genome instability and carcinogenesis. In addition, XPV patients are defective in a translesion synthesis activity specialized in bypassing UV-induced lesions, and share symptoms with other XP patients. This review will focus on the evidence that elucidates the link between defective NER, genetic instability, and oncogenesis.