[Carcinogenic effect of metals]

Some metals are essential oligo-elements for man. However, if the body load of these same metal derivatives becomes excessive they may be responsible for deleterious effects, particularly cytotoxic ones. Metals are divided into four categories: potent carcinogens; presumptive carcinogens with a documented cocarcinogenic effect; ascertained cocarcinogens; metals with no demonstrated carcinogenic or cocarcinogenic effect. The most common tumors induced by metals are those of the lung. Arsenic induces cancer of the lung and skin, beryllium may induce lung cancer, the effects of cobalt are dubious, cadmium can induce cancer of the lung and, above all, prostate, the role of iron is uncertain, hexavalent chrome may induce cancer of the lung and nasal fossae, nickel is responsible for cancer of lung and nasal fossae. Our understanding of metal carcinogenesis is clearly insufficient and more experimental research and epidemiologic studies addressing this subject are needed.