Since ER status is predictive of better prognosis following treatment37–39, we investigated whether the ERs, ERα, most commonly studied37,40 and ERβ, considered as predictive marker of Tamoxifen resistance in breast tumours yet not clinically assessed41–43, showed any association with markers of hypercoagulation that could hold predictive value for thrombotic propensity relative to tumour phenotype. The gene discussed is ESR2; the disease is breast neoplasm.