Progesterone receptor gene polymorphisms and risk of endometriosis: results from an international collaborative effort

Objective To investigate the association between self-reported endometriosis and the putative functional promoter +331C/T single nucleotide polymorphism (SNP) and the PROGINS allele. Design Control subjects from ovarian cancer case-control studies participating in the international Ovarian Cancer Association Consortium. The majority of controls are drawn from population-based studies. Setting An international ovarian cancer consortium including studies from the Australia, Europe and the United States, Patients 5,812 White female controls, of whom 348 had endometriosis, from eight ovarian cancer case-control studies. Interventions None. Main Outcome Measures Genotypes for the +331C/T SNP and PROGINS allele and a history of endometriosis. Results The occurrence of endometriosis was reduced in women carrying one or more copies of the +331 T allele (OR=0.65; 95% CI: 0.43–0.98, p=0.042), whereas there was no association between the PROGINS allele and endometriosis (OR=0.94, 95% CI 0.76, 1.16). Conclusions Additional studies of the +331C/T variant are warranted given the current finding and the equivocal results of previous studies. The +331 T allele has been shown to result in a reduced PR-A to PR-B ratio and if the observed association with endometriosis is confirmed it would suggest that this ratio is important for this disease