ABSTRACT
The risk for skin cancer, especially basal cell carcinoma (BCC) and malignant melanoma, is closely related to the number of sunburn episodes in the person’s life, which is influenced by the skin color. Very light skin color may increase skin cancer incidence up to 1100-fold compared to darkly pigmented individuals depending on the level of ultraviolet radiation (UVR) exposure. Skin pigmentation is primarily regulated by locally produced melanocyte-stimulating hormone alpha that acts as paracrine and/or autocrine mediator of UVR-induced pigmentation. Intermittent high-dose solar exposure is thought to provoke BCC rather than regular moderate doses of UVR. Epidemiology supports a relationship between solar radiation and skin cancer, but terrestrial sunlight contains visible and infrared as well as UVR. A definitive role for UVR was first established in animals. The specificity of UVR-induced mutations enables the detection of the early molecular events in skin carcinogenesis.
