Role of UVA in the pathogenesis of melanoma and non-melanoma skin cancer. A short review.

It is well established, at least in mice, that not only ultraviolet C (UVC) or ultraviolet B (UVB), but also ultraviolet A (UVA) is able to induce squamous cell carcinomas. Results from animal models, epidemiological studies, and clinical observations suggest that UVA might play an important role in the pathogenesis of malignant melanoma as well. In contrast to UVC or UVB, UVA is hardly able to excite the DNA molecule directly and produces only few pyrimidine dimers. Oxidative DNA base damage, generated indirectly through photosensitizers, might be responsible for the mutagenic and carcinogenic properties of UVA. This is supported by differences in mutation spectra induced by UVA and UVB in mammalian cells and tumors. Avoidance of natural and artificial UVA sources is recommended, especially for melanoma-prone individuals.