PIK3CA and neoplasm: In particular, Andrè et al., reported that patients harboring low/absent PTEN tumor expression by immunohistochemistry or a hyperactive PI3K pathway (defined as either low/absent PTEN expression or PTEN mutations or PIK3CA activating mutations or AKT1 E17K mutations) experienced a significant progression-free survival (PFS) improvement with the addition of Everolimus to chemotherapy plus Trastuzumab, as compared to patients without these alterations [55].