CDKN2A and gastric cancer: Although TSG silencing is more commonly attributed to promoter hypermethylation, hypomethylation-induced genomic instability may lead to structural alterations, mutations, or deletions in TSG loci such as TP53 and CDKN2A, other gastric cancer-related tumor suppressor genes such as CDH1, RASSF1A, and MLH1 impairing their tumor-suppressive functions (Heydari et al., 2024).