Prostate cancer genetics.

Prostate cancer (PC) is the most frequent malignant tumor among men over 50 years old. Its incidence varies according to countries and ethnic groups. Known risk factors are race and positive family history of the disease. Familial aggregation (at least 2 cases in the family) is observed in about 20% of cases and a hereditary form of PC, compatible with a Mendelian inheritance, in 5%. This proportion increases with younger age at diagnosis. Eight putative loci are already identified for hereditary PC but undoubtedly, others will be found in forthcoming studies. The genetic heterogeneity observed in hereditary PC reflects variety of origins of the studied families. Agreggation of PC and other cancers in some families suggests the involvement of common susceptibility genes. In other familial form and in sporadic cases, the genetic component should be polygenic: PC wouldn't result from segregation of a major gene mutation transmitted according to a monogenic inheritance, but rather to sharing of alleles at many loci, each contributing to a small increase in cancer risk. Indeed, several genetic polymorphisms were associated with an increased risk of developing PC and could explain the variations of PC incidence observed between populations.