Loss of heterozygosity at pseudoautosomal regions in human breast cancer and association with negative hormonal phenotype.

To determine the possible involvement of X-linked genes in breast cancer, a group of human sporadic breast carcinomas were analyzed for loss of heterozygosity (LOH) at 12 polymorphic loci distributed along the whole chromosome X. LOH by at least one marker was observed in 14 of 46 informative cases and two regions of consistent LOH in 10 of 14 (71.4%) were identified at pseudoautosomal regions (PAR). Allelic losses in these regions significantly correlated with the absence of estrogen receptors (P<0.05) and concordant absence of either estrogen (ER) or progesterone (PgR) receptors (P<0.05). The clinicopathological parameters evaluated, (like age, menopausal status, histological type, tumor size, nodal status, grading, ploidy, labeling index, and S-phase fraction), were independent from the LOH present in the PAR regions of X chromosome. This study suggests a role as a prognostic factor for LOH and ER(-)/PgR(-) when associated and provides some additional support for the existence of candidate tumor suppressor gene on PAR regions, whose alteration may play a role in breast cancer development and progression.