Furthermore, to investigate whether FoxO1 and FoxO3a directly affect Klf15 expression, adenoviruses that express constitutive active mouse FoxO1 and human FoxO3a (FoxO1ADA6KR and FoxO3aAAA, respectively) were transduced into HepG2 and Huh7 hepatoma cells, leading to a result that FoxO1 and FoxO3a also upregulated intrinsic KLF15 expression similar to G6PC known as a FoxOs target in hepatocytes as shown in Figures 2A–2J. This evidence concerns the gene G6PC1 and hepatocellular carcinoma.