MTOR and hepatocellular carcinoma: The phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling pathway plays crucial roles in regulating the cellular processes, including cell proliferation, survival, differentiation, angiogenesis, and apoptosis that are dysregulated in the drug-resistant HCC cells [10,11,12].