Furthermore, it is established in the literature that chronic TMX use (for ≥5 years) could reduce the risk of death from PR+ ER+ breast cancer (Salami & Karami-Tehrani, 2003; Karn et al., 2010; Group (EBCTCG), 2011; Hong et al., 2016; Drăgănescu & Carmocan, 2017) but when is used with potent inhibitors of CYP2D6 could be a risk of mortality (Donneyong et al., 2016). Here, ESR1 is linked to breast cancer.