It's All about Position: The Basal Layer of Human Epidermis Is Particularly Susceptible to Different Types of Sunlight-Induced DNA Damage

In this issue, Tewari et al. show that although UVB most effectively causes cyclobutane pyrimidine dimers (CPDs) at the human epidermal surface, UVA-induced CPDs predominate in the basal layer. Previous studies found higher accumulation of UVA-induced 8-oxo-7,8-dihydro-2'-deoxyguanosine and mutations in the basal layer. Therefore, the epidermal basal layer is particularly sensitive to UVA-induced genetic damage and the formation of mutations.