[Colorectal cancers at the time of molecular genetics]

One must always keep in mind the distinction between constitutional genetic mutation and acquired or somatic genetic mutation. Our knowledge of the syndromes resulting from germ line mutations and the detailed clinical description of the diseased patients have been the key to research into the field of susceptibility to colorectal cancer. Research has now entered a new era due two major advances. First it is now possible to identify persons at risk, carriers of constitutional defects involving genes responsible for colorectal cancer. Secondly, it is now possible to better identify high risk lesions based on histological examination and use of molecular markers. In the future, further progress will allow us to analyse acquired mutations. These advances open the way to new diagnostic approaches and raise a considerable number of questions concerning the ethics of molecular diagnosis and treatment.