Investigation of the effect of UV irradiation on DNA damage: Comparison between skin cancer patients and normal volunteers

Background Susceptibility to environmental carcinogenesis is the consequence of a complex interplay between intrinsic hereditary factors and actual exposure to potential carcinogenic agents. Exposure to sunlight is the primary etiological agent for basal cell carcinoma (BCC). Aim The aim of this study was to determine the effects of different ultraviolet (UV) doses on DNA damage in epidermal keratinocytes in vivo and to elucidate if patients with BCC are more susceptible to UV-induced DNA damage in comparison with normal healthy volunteers in response to solar simulator radiation (SSR). Materials and Methods Skin biopsies obtained post-UV irradiation from both normal healthy volunteers and BCC patients were analyzed for DNA damage, using immunohistochemical approach with TDM-2 antibody, which binds specifically to cyclobutane pyrimidine dimmers (CPDs). Results In both normal volunteers and BCC patients, the peak of CPD-positive cells occurred at 4.5 h post-SSR. There was a statistically significant difference in CPD positivity between BCC patients and normal volunteers, at time points (from 4.5 h to 48 h post-SSR). For a given dose of SSR based on each individual minimal erythema dose (MED), a greater number of CPD-positive cells could be shown. Conclusions This study has shown for the first time and in vivo in human volunteers that BCC patients are more susceptible to UV-induced DNA damage in comparison with normal healthy volunteers.