PIK3CA mutations and PIK3R1 underexpression show opposite effects on patient outcome and could become useful prognostic and predictive factors in breast cancer.
PIK3CA mutations were more frequent in low-risk luminal BCs (e.g., grade 1 nodev 3, node-negative v -positive), confounding the relationship between mutations and outcome.
PIK3CA mutation status does not change in the majority of patients with breast cancer and the acquisition of mutations in PIK3CA is not responsible for the development of endocrine resistance.
PIK3CA hotspot mutations are present at a relatively high frequency in CTCs and their presence is associated with worse survival in patients with breast cancer with metastasis.
PIK3CA mutation may contribute to the poor outcome of ER positive breast carcinomas, providing evidence for the combination of PI3K/AKT/mTOR inhibitors and endocrine therapy.
PIK3CA mutations in breast cancer tissues that were taken prior to the initiation of neoadjuvant chemotherapy were identified in 729 operable primary breast cancer patients who received neoadjuvant chemotherapy.
PIK3CA mutations showed surprising clinicopathological features in breast cancer patients, as incidence of lymph node invasiveness is increased in the patients with PIK3CA mutation.
PIK3CA mutations are seemingly the most common driver mutations in breast cancer with H1047R and E545K being the most common of these, accounting together for around 60% of all PIK3CA mutations and have promising therapeutic implications.