ESR1 and breast cancer: In particular, ER positivity is linked to the methylation of specific genes, including RASSF1A, CCND2, GSTP1, and TWIST. Vesuna and colleagues [25] reported that TWIST, a gene overexpressed in high-grade BC, promotes downregulation of ER through the recruitment of HDAC1 and reduced expression of ER through the recruitment of DNMT3B.