TMPRSS6 and hepatocellular carcinoma: Similar results were also observed in the hepatocellular carcinoma cell line Hep3B, a cell line expressing TMPRSS6 endogenously (Figure 4B).39 However, the internalization rate seemed slower in Hep3B cells when compared to HEK293 transfected cells as more TMPRSS6‐1 remain at the cell surface at 30 minutes (Figure 4A, B).