title: New insights on PI3K/AKT pathway alterations and clinical outcomes in breast cancer.
abstract: PI3K/AKT signaling pathway plays an important role in tumorigenesis and regulates critical cellular functions including survival, proliferation and metabolism. PIK3CA mutations and AKT activation by phosphorylation (pAKT) are often detected in many cancers and especially at high frequencies in breast cancer. Mounting data suggest that PIK3CA mutations or pAKT are mostly associated with better or insignificant outcomes in estrogen receptor-positive (ER+) early stage breast cancer and tend to be with worse prognosis in ER- disease. pAKT expression has been identified to predict paclitaxel chemotherapy benefit in node-positive breast cancer. Preclinical and neoadjuvant trial data suggest that PIK3CA alterations confer resistance to HER2-targeted therapy and are associated with lower pathological complete response (pCR) rate in HER2-positive breast cancer. However, recent results from randomized clinical trials of adjuvant and metastatic settings show that patients with mutant and wildtype PIK3CA tumors derived similar benefit from anti-HER2 therapy. This article, with our new insights, aims to decipher the mixed data and discusses the influence of the potential confounding factors in the assessments. We also share our views for validation of PI3K/AKT alterations in relation to clinical outcome in the context of specific breast cancer subtypes and treatment modalities towards further advance of the precision medicine for breast cancer treatment.
authors.affiliation: National Clinical Target Validation Laboratory, Division of Cancer Treatment and Diagnosis, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA. Electronic address: Sherry.Yang@nih.gov.
authors.forename: Sherry X
authors.initials: SX
authors.lastname: Yang
authors.affiliation: Biometrics Research Branch, Division of Cancer Treatment and Diagnosis, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.
authors.forename: Eric
authors.initials: E
authors.lastname: Polley
authors.affiliation: Women's Malignancies Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.
authors.forename: Stanley
authors.initials: S
authors.lastname: Lipkowitz
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D014408:Biomarkers, Tumor / Q000032:analysis / Q000235:genetics; D001943:Breast Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000473:pathology; D058534:Class I Phosphatidylinositol 3-Kinases; D005260:Female; D006801:Humans; D009154:Mutation; D009367:Neoplasm Staging; D051058:Oncogene Protein v-akt / Q000235:genetics*; D017239:Paclitaxel / Q000494:pharmacology*; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000235:genetics; D015398:Signal Transduction / Q000235:genetics; D016896:Treatment Outcome
chemical_list: D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D058534:Class I Phosphatidylinositol 3-Kinases; D051058:Oncogene Protein v-akt; D017239:Paclitaxel; D019869:Phosphatidylinositol 3-Kinases; D018719:Erb-b2 Receptor Tyrosine Kinases; C484760:PIK3CA protein, human
keywords: Breast cancer; Chemotherapy; HER2; PIK3CA mutations; Paclitaxel; pAKT