[Selenium compounds and carcinogenesis]

Starting with a brief outline of the general toxic effects of selenium compounds, their biological importance for the organism as a trace element and with an analysis of the different hypotheses on the action mechanism of selenium and selenium compounds, a survey is provided in which way selenium compounds may influence malignant transformation and related processes in vivo and in vitro. Furthermore, observations are viewed on the effects of selenium compounds on spontaneously developing, chemically or virally induced tumors. Based on the data available so far it cannot, at present, be assessed whether selenium and its compounds can be used in the future for chemoprevention of cancer.