Ultraviolet light-induced chromosomal aberrations in cultured cells from Cockayne syndrome and complementation group C xeroderma pigmentosum patients: lack of correlation with cancer susceptibility.

Both Cockayne syndrome (CS) and xeroderma pigmentosum (XP) are inherited diseases with defective repair of damage induced in DNA by UV. Patients with XP, but not those with CS, have an increased susceptibility to formation of sunlight-induced skin tumors. We determined the frequency of UV-induced chromosomal aberrations in cultured lymphoblastoid cell lines from five CS patients and three complementation-group-C XP patients to determine whether such aberrations were abnormally increased only in the XP cells. We found that CS cells had the same abnormally increased number of induced aberrations as the XP cells, indicating that the number of UV-induced aberrations in XP group C cells does not account for the susceptibility of these XP patients to sunlight-induced skin cancer.