Next, to explore the role of Naa20 on tumorigenic features in several HCC cell lines, including Hep3B, SK-Hep1, and HepG2, cells were transiently transfected with expression vectors of wild-type human Naa20 or the catalytically inactive mutant Naa20 YF (Y123F; Supplementary Fig. S2a, b)28, followed by cell counting and MTS assays to determine the cell growth rate and cell viability, respectively, at different times. Here, NAA20 is linked to hepatocellular carcinoma.