TGFB1 and hepatocellular carcinoma: The proliferative variant of HCC is more aggressive and associated with high serum level of α-fetoprotein (AFP), expression of progenitor cell phenotype, tumor protein 53 (TP53) mutations, and activation of transforming growth factor β (TGF-β), hepatocyte growth factor receptor (MET), protein kinase B (AKT), and insulin-like growth factor (IGF) 2 pathways [4].