IGF1R and hepatocellular carcinoma: It has been demonstrated that abnormal methylation occurs at the level of HCC cells compared to adjacent parenchymal cells, with the hypomethylation (e.g., IGF1R, HGF, HLA-DQA1, PIK3CG, MAPK10, KDR, FGFR1, GNGT2, PLCB4, ADCY2), and hypermethylation of certain genes (e.g., APC, HIST1H4F, FGF19, FZD1, LPAR2, HIST1H3F, HIST1H3G, HIST1H3J, PMAIP1, RASGRF2) inducing tumorigenic metabolic alterations.