Abnormal lymphocyte response to u.v. radiation in multiple skin cancer

The lymphocyte response to u.v. radiation (254 nm) was investigated by two different methods in 29 unselected patients with multiple epidermal cancer. The u.v.-induced DNA synthesis was determined as the increase in incorporation of [3H]thymidine in irradiated cells compared with nonirradiated cells after incubation for 2 h. The u.v. tolerance was measured as the u.v. dose necessary for 50% reduction in phytohemagglutinin-stimulated lymphocyte proliferation. Patients with both squamous cell differentiated tumors and basal cell carcinomas had very high u.v.-induced DNA synthesis values (p less than 0.01, when compared with patients with basal cell carcinoma only and p less than 0.005, when compared with controls). The u.v. tolerance in patient lymphocytes was considerably lower than in control lymphocytes (p less than 0.001), with the lowest values occurring in patients with clinical sun intolerance (p = 0.05, when compared with the remaining patients). These investigations may be of predictive value in skin carcinogenesis.