ERα has been associated with sustained cell proliferation (and other cancer hallmarks) and ERβ has been linked to amelioration of ERα’s cancer promoting effects (Saji et al., 2000; Lazennec et al., 2001; Palmieri et al., 2002; Shaaban et al., 2003; Paruthiyil et al., 2004; Chang et al., 2006; Mfenyana et al., 2008; Visser et al., 2013; Zhou and Liu, 2020). The gene discussed is ESR2; the disease is cancer.