PIK3CA and breast carcinoma: PI3K/AKT/mTOR hyperactivation is common finding in cancer, and somatic mutations in PIK3CA/AKT/mTOR axis, like gain-of-function mutations of PIK3CA gene and loss/low expression of the regulatory molecule PTEN, have been identified as responsible of resistance to conventional therapeutical regimens in different tumours, including breast cancer [12].