CDKN2A and gastric neoplasm: The H. pylori virulence factor CagA hijacks SHP-2 to activate DNMT1 and DNMT3B, inducing hypermethylation of CpG islands in CDKN2A/p16, RPRM, RUNX3, and LOX promoters, thereby establishing a CpG Island Methylator Phenotype (CIMP) in 30–40% of gastric tumors (Kontizas et al., 2020; Bhattacharjee et al., 2024).