[Genetic factors in the etiology of breast cancer (author's transl)].

A review of literature shows that, at present, genetic factors are difficult to distinguish from environmental factors. A number of studies have put into light relationships between factors tranmetted genetically and an increased risk of breast cancer in some women. This might be a reflect of the transmission of a certain susceptibility. However, one of these factors alone cannot explain the increase of the risk. Most likely, as for many types of cancers, the development of breast cancer is due both to a multigenic transmission of a certain susceptibility and to the action of environmental factors. Though, epidemiological studies make possible to identify a high risk population. A regular follow-up of this population would permit early diagnosis and possibly prophylactic measures concerning the known environmental factors, and in particular hormonal factors.