MOLECULAR-BIOLOGY OF HEREDITARY PREDISPOSITION TO HUMAN CANCERS

The physiological action of antioncogenes is repressing cell growth, a nd they are involved in the tumorigenesis when their two copies are ab sent or non functional. One of these copies may be altered and inherit ed from the parents, predisposing patients to cancer, the second mutat ed copy being acquired during the life span. The retinoblastoma gene r esponsible of retina tumors in the child, was the first antioncogene t o be cloned and is the paradigm for molecular mechanism studies of her editary cancers. Hereditary cancers are rares, a few of the genes invo lved in are known as TP53 (for the Li-Fraumeni syndrome), NF1 (for the von Recklinghausen neurofibromatosis), WT1 (for the Wilms tumor). APC (for the familial adenomatous polyposis). More hereditary cancer gene s were located on the genome but are still unknown. Interestingly canc ers hereditary predisposition can account for about 10 per 100 cases o f common cancers as breast cancers or colon cancers. A better clinical definition of these hereditary syndromes will help to discover the re sponsible genes and to precise the genetic counselling for the affecte d families. The current knowledges of those differents situations are presented. A discussion is initiated about the pitfalls of predictive medecine through genetic analyses, like genetic discriminations and eu genism.