Skin melanomas may arise through at least two different pathways dependent upon the host characteristics and prevailing environmental factors. Epidemiological and immunohistochemical investigations assessed the body site distributions of cutaneous melanoma in populations living in areas of high (Queensland, Australia) or low (Scotland, UK) ambient sunlight. Similar age-dependent anatomical distributions of melanoma were found in both groups despite a fivefold difference in absolute melanoma incidence. Among those aged ≤ 40 years, melanomas occurred most frequently on trunks and limbs; in those aged > 60 years, they were most prevalent on the face, head and neck. Heterogeneity was further explored via melanoma-related proteins (p53, MAPK, p16 and Brn-2). In a sample of 129 ...