These “repressed” genes include ESR1 (gene encoding ERα), ERBB2, GATA3, and ZNF217 (Fig. 2C)—all critical genes to the etiology of breast cancer (Sørlie et al. 2001; Usary et al. 2004; Oh et al. 2006; Cohen et al. 2015). The gene discussed is ESR1; the disease is breast cancer.