[Genetics and cancer: advances and perspectives].

Cancer genes can be ranged in three families: oncogenes, stimulating cell divisions; antioncogenes, blocking cell division; anti-apoptotic genes, blocking programmed cell death. Tumor progression usually results from cooperation between modifications of genes belonging to these different families. The familial predispositions to cancer are most frequently due to mutations of antioncogenes or of repair genes; in this later case, the original mutation results in abnormal DNA repair, then in accumulation of somatic mutations which could involve cancer genes. Recently, genes predisposing to familial forms of breast and colon cancers have been identified. Knowledge of such genes leads to possible presymptomatic prediction of the disease, but the preventive possibilities seem to be limited, today, to a preventive surgical exeresis. In the future, it would be desirable that elucidation of the mechanisms of cancer predisposition leads to less aggressive preventive or curative treatments.