MTOR and hepatocellular carcinoma: Different molecular mechanisms responsible for initiating and promoting HCC have been identified, such as receptor tyrosine kinase pathways, the Ras mitogen-activated protein kinase (Ras/Raf/MAPK), the phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR), the Wnt/β-catenin signaling pathway, the ubiquitin/proteasome degradation, and the hedgehog signaling pathway [3].