MTOR and hepatocellular carcinoma: Potential roles of miR-221 have been reported in many cancers such as hepatocellular carcinoma formation in cirrhotic liver by targeting the tumor suppressor DNA-damage inducible transcript 4 (DDIT4), modulating the mTOR pathway, or in bladder cancer cells by modulating p53 upregulated modulator of apoptosis [54,55].