PTEN and cancer: In fact, mTOR signalling is enhanced across a number of cancer types [104], and can be regulated by a number of cancer-driving genetic alterations including PIK3CA and KRAS mutations or loss of the tumour suppressor PTEN. As such, mTOR in cancer is an attractive therapeutic target, and a number of strategies have been explored to effectively inhibit mTOR biology, including use of Rapamycin, the inhibitor of mTORC1 [105].