[Conclusion and future prospects]

The genetic events which are associated with tumorigenesis concern two classes of genes: proto-oncogenes and anti-oncogenes. The first code for products which take part in the positive control of cellular proliferation; the second code for products which are involved in the negative regulation of cell growth. The identification of genes involved in the genetic predisposition to some cancers can be used in predictive medicine, while the observations on proto-oncogenes are already of prognostic value in some instances. In the future they will lead to new therapeutic approaches.