ESR1 and malignant colon neoplasm: ER-α was highly expressed in human breast and ovarian cancer cell lines (O’Donnell et al., 2005; Sotiriou and Pusztai, 2009; Miyoshi et al., 2010; Siersbæk et al., 2018), while its mRNA was not detected in human colon cancer cell lines, such as HCT8 and HCT116 (Fiorelli et al., 1999).