Ultraviolet-specific mutations in p53 gene in skin tumors in xeroderma pigmentosum patients.

Mutations in the p53 gene were identified in five of eight non-melanoma skin tumors in the sun-exposed areas of xeroderma pigmentosum patients by the polymerase chain reaction and single strand conformation polymorphism analysis followed by sequencing of the DNA. All mutations occurred at the dipyrimidine sites, indicating that they were caused by UV irradiation. Two tumors had multiple mutations, and four tumors had nonsense mutations. Since xeroderma pigmentosum patients are extremely sensitive to UV, the solar UV should have caused the mutations in the p53 gene and the mutations must have played a significant role in UV tumorigenesis.