STAT5A and hepatocellular carcinoma: To verify a functional role for Stat5 binding to the mouse Tmprss6 promoter on Tmprss6 mRNA expression, we studied the effect of Stat5 overexpression on Tmprss6 promoter activity in vitro using a mouse Tmprss6 promoter luciferase construct (Tmprss6 wt-Luc) in a mouse hepatoma cell line (hepa 1–6 cells) since this construct was not functional in the human cell line Hep3B (data not shown).