MTOR and liver cancer: So far as we known, there are many signaling pathways associated with liver cancer invasion and metastasis, for instance the phosphoinositide 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) and rat sarcoma (Ras)/Raf/MEK/extracellular signal-regulated kinase (ERK) signaling pathways, which alters the biological activities of cancer cells through induction of malignant transformation, inhibition of apoptosis, enhancement of proliferative and metastatic capabilities, and eventually leads to the malignant progression of tumors and poor prognosis of the patients [23].