Polymorphism of the estrogen receptor-β gene in breast cancer

Microsatellite polymorphism may influence gene expression or receptor signaling function. In cancer, microsatellite sequences, even when located in non-coding regions of a gene, are capable of modif ring the susceptibility to carcinogenic factors. The estrogen-receptors (ER) alpha and beta are involved in breast oncogenesis, with different prognosis significance. They mediate different and complex pathways. Recently, the expression of the ERbeta in breast tumors has been shown to be a marker for good prognosis for breast cancer (BC). Although this piece of information needs further testing, the involvement of the ERbeta in BC signaling processes has been clearly demonstrated. The goal of the present study was to gain insight into the genetic polymorphism of ERbeta, and its possible relationship to BC pathogenesis regarding estrogen dependence. We conducted a case-control study comprising 27 BC samples and 30 control samples, matched by age and hormonal status. Our results indicate that the length of the ERbeta genotype variants oscillates between 149-169 bp. Clearly, the overall ERbeta distribution had a bimodal distribution with a majority of alleles ranging between 161 and 165 pb. A group of ERbeta alleles was significantly shorter (below 159 bp) with a predominant peak at 155 pb. A comparison of the length of the ERbeta genotypes revealed that short alleles [below 21 cytosine (C) and adenosine (A) repeats - 159 bp] were significantly more frequent in BC patients (42.6%) compared to controls (18.3%; t = -2.50; p = 0.0 13). In conclusion. (CA)n polymorphism at the ERP locus may represent a modulator factor of BC risk.