Efforts to understand the tumor suppressor role of COMT in cancer cells in hormone receptor positive tumors were previously recorded: Estrogen (17β-estradiol) decreases the mRNA levels of COMT in time- and dose-dependent manner mediated by estrogen responsive elements in its proximal promoter and CCAAT/enhancer binding sites in its distal promoter68,69. This evidence concerns the gene COMT and neoplasm.