MTOR and cancer: Numerous selective pharmacological inhibitors of the PI3K/Akt/mTOR pathway have being developed, many of which are currently being tested in clinical trials, and are reported to be effective in the treatment of several types of cancer by exerting antiproliferative and proapoptotic effects and restoring tumor cell sensitivity to chemotherapy, radiotherapy, and hormonal treatment, thus showing great potential for targeted antitumor treatment [33,34,35].