SOD2 and hepatocellular carcinoma: To assess the catholicity of FoxM1 upregulation by MnSOD overexpression in sustaining carcinogenicity and stemness in HCSLCs, we selected two additional established hepatic carcinoma cell lines, including HepG2 and SMMC-7721 cells, to compare MnSOD and FoxM1 expression levels, sphere and colony formation capabilities and protein expression levels of CD133, CD44 and ALDH1 between HepG2 or SMMC-7721 cells and the corresponding HCSLCs.