TET1 and hepatocellular carcinoma: Next, 2 μM sorafenib was used to treat shTET1 and control HCC cells, and alkaline comet assay showed that TET1 knockdown significantly increased the length of DNA tails indicating that DNA damage was more severe in shTET1 Huh-7 cells (Fig. 3C) and HepG2 cells (Fig. S3A).