Regarding mTOR and HER, and given that HER-2 expression is significant in the over-activating of mTOR signaling in breast cancer, and that HER family receptors can promote PI3K-mTOR signalling [123], resistance to HER-2 therapies in breast cancer, particularly lapatinib (a dual EGFR (HER-1 and HER-2) inhibitor) and trastuzumab (an antibody-based drug), is significantly correlated with mTOR signaling [124,125]. Here, PIK3CA is linked to breast cancer.