PTEN and breast cancer: Importantly, the PyMT oncogene that drives the cancer model used in our study is a strong inducer of the PI3K-AKT-mTOR signaling axis [41].This is relevant because the majority of human breast cancers show a hyper-activation of this pathway due to activating point mutations, gene amplifications, or inactivation of phosphatases such as PTEN [52,53].