Xeroderma pigmentosum variant associated with multiple skin cancers and a lung cancer.

A 65-year-old Japanese man with a xeroderma pigmentosum (XP) variant, XP127TO, is described. The XP127TO skin fibroblasts exhibited the typical XP variant characteristics of a 1.5-fold higher sensitivity than normal cells to the lethal effect of 254 nm ultraviolet (UV) light and the normal level of unscheduled DNA synthesis induced by 254 nm UV. Caffeine dose-dependently increased the cytotoxic effect of 254 nm UV on XP127TO cells. Clinically, the patient developed not only 3 cutaneous squamous cell carcinomas on sun-exposed areas but also an adenocarcinoma of the upper lobe of the right lung. A review of the 14 documented Japanese XP patients with nonskin malignancies indicates that the incidence of nonskin malignancy in XP patients is much lower than that of skin cancer in XP but higher than that in the general population.