ESR2 and breast cancer: Many relevant studies in BC have been associated with different variants of the ESR2 gene, including the rs1256049, rs4986938, and rs1256030 variants (Försti et al., 2003; Maguire et al., 2005; Tsezou et al., 2008; Yu et al., 2011; Karlsson et al., 2016; Haldosén, Zhao & Dahlman-Wright, 2014; Mahdavipour et al., 2017; Ghali et al., 2018).