TGFB1 and hepatocellular carcinoma: Global hypomethylation of DNA is common in cancer, promoting chromosomal instability and reactivation of endogenous retroviral sequences.448 The analysis based on DNA methylation profiles of 304 HCC patients discovered a CpG methylation signature that is correlated with patient survival, among which, IGF, PI3K, TGF-β and WNT pathways were mostly dysregulated in HCC by DNA methylation.449 DNA is wrapped around histone proteins to form nucleosomes, where histone proteins undergo various PTMs such as acetylation, methylation, phosphorylation, and more.