Hypermethylation of most genes such as APC, E-cadherin, UCHL1, SPG20, RASSF1A, SFRP2, CDH1, THBS1, SOX17, Wif-1, RNF-180, MED12L, HMLH1, MGMT, FLNC, LOX, HOXD10, BNIP3, and PCDH10 was significantly associated with adverse prognosis in GC (Balgkouranidou et al., 2015; Cheung et al., 2012; Hu X et al., 2021; Ikoma et al., 2006; Karamitrousis et al., 2021; Necula et al., 2019; Pimson et al., 2016; Wang et al., 2015; Yan et al., 2021; Yu et al., 2012; Zhang et al., 2014) (Table 2). The gene discussed is MGMT; the disease is gastric cancer.