[UV exposure, skin cancer and decrease in the ozone layer]

All over the world a remarkable increase in malignant tumors of the skin is reported. More than 90% of them are localized in areas of the skin exposed to sunlight. The incidence of malignant melanomas of the skin is tenfold higher today than 40 years ago. Experimental data and results of epidemiological studies indicate two different risk patterns of UV exposure for the development of skin cancer. The cumulative UV-light exposure during lifetime induces--especially in light-sensitive individuals older than 60 years--actinic elastosis, precanceroses and squamous cell carcinomas as well as lentigo maligna melanomas. Intense UV exposure in childhood and youth may lead to development of superficial spreading melanomas and nodular melanomas between the age of 20 and 40. The reduction of ozone in the stratosphere could still contribute to a higher incidence of tumors of the skin in the next decades. The evident role of UVB light in the induction of tumors of the skin offers the possibility for preventive strategies.