Cancer, warts, and sunshine in renal transplant patients. A case-control study

94 renal transplant patients were examined for the presence of cutaneous malignancies, actinic keratoses, warts, and cutaneous fungal infection, and a history was taken of infection with herpes simplex and herpes zoster. Each patient had a control matched for age, sex, and sun exposure. Of the 17 patients with high exposure to sunshine (more than 3 months in a tropical or subtropical climate or more than 5 years in an outdoor occupation), 2 had squamous cell carcinoma and 7 actinic keratoses. These lesions did not occur in the other renal transplant patients or the control group. The immunosuppressive effect of ultraviolet radiation in the sunburn spectrum (290-320 nm) in man and animals may be related to the increased incidence of cutaneous malignancy, actinic keratoses, and warts. Transplant patients should be under regular surveillance for the early detection and treatment of premalignant cutaneous lesions, and they should receive advice on avoiding sun exposure.