EDITORIALS Molecular Epidemiology of Basal Cell

The skin is a large organ directly exposed to physical and chemical carcinogens, which produce frequent cancers. Studies of skin cancer have figured prominently in cancer epidemiology (including that of occupational cancers such as scrotal cancers in chimney sweeps) and in laboratory investigations of chemi-cal, physical, and viral carcinogenesis [reviewed in (/)]. Ultraviolet (UV) radiation (UVB [wavelengths of 280-320 nm] and to a lesser extent UVA [wavelengths of 320-400 nm] in sun-light) are considered to be the major etiologic agent of squamous cell carcinoma (SCC), basal cell carcinoma (BCC), and mela-noma (2-4). Autosomal recessive, e.g., xeroderma pigmento-sum, and autosomal dominant, e.g., nevoid BCC syndrome (Gorlin's syndrome), inherited cancer-prone conditions have been identified [reviewed in (7)]. Germline mutations in specific cancer susceptibility genes involved in nucleotide excisio