TET2 and hepatocellular carcinoma: It has been shown that m5C expression levels and regulators NSUN4, NSUN5, DNMT1, TET2, and ALYREF are significantly upregulated in HCC and are related to poor prognosis in HCC patients (Blanco et al., 2016; He et al., 2020a; He et al., 2020b; He et al., 2020c; Du et al., 2020;Zhang et al., 2020e; Cui et al., 2021b; He et al., 2021; Liu et al., 2022).