ESR1 and essential hypertension: The global DNA methylation level decreased in patients with ischemic cardiac disease, atherosclerosis or essential hypertension, while the methylation level of the estrogen receptor (ER)-α or 11 β-hydroxysteroid dehydrogenase 2 (11βHSD2) promoter increased (Friso, et al., 2008; Huang, et al., 2009; Smolarek, et al., 2010; Ying, 2000).