ESR1 and breast cancer: Our findings are also consistent with those of Winder who found better survival outcomes for women with HR+ breast cancers treated with the anti-estrogen tamoxifen who carry the T allele of rs2016347 [40], as well as with those of Bhargava who found that while IGF1R overexpression is most common in HR+ relative to HR− breast tumors, patients with HR+ breast cancers expressing lower levels of IGF1R have significantly better survival outcomes following ER-targeted endocrine therapy [56].