Recently, it has been reported that DNA methylation of G protein subunit beta 4 (GNB4) can be a potential target for anti-oestrogen resistance treatment of breast cancer and a potential marker for diagnosis and prognosis evaluation of gastric cancer induced by Helicobacter pylori [38,39] The Riplet gene (also known as Ring finger protein 135, RNF135) has also been found to be involved in the regulation of proliferation and metastasis of triple-negative breast cancer [40], and its promoter methylation is related to the immune invasion and prognosis of HCC [41]. The gene discussed is GNB4; the disease is gastric cancer.