title: Role of HER3 expression and PTEN loss in patients with HER2-overexpressing metastatic breast cancer (MBC) who received taxane plus trastuzumab treatment.
abstract: BACKGROUND
  The aim of this study was to investigate the role of human epidermal growth factor receptor (HER3) and PTEN expression in patients with HER2-overexpressing metastatic breast cancer (MBC).
  
  
  METHODS
  One hundred twenty-five MBC patients who were treated with taxane plus trastuzumab chemotherapy as first-line therapy were included in this analysis. Immunohistochemical (IHC) staining with HER3 and PTEN antibodies were conducted retrospectively.
  
  
  RESULTS
  Patients who had negative HER3 staining (62.4%) had a better progression-free survival (PFS) than did those who had positive HER3 staining (P=0.001; median PFS, 21 vs 11 months). Patients who had a PTEN score >20 (78.1%) showed longer PFS than did those with a PTEN score ≤20 (P=0.006; median PFS, 13 vs 9 months). Patients who had a PTEN score >20 exhibited a longer overall survival (OS) than did those with a PTEN score ≤20 (P=0.005; median OS, 48 vs 25 months). HER3 negativity and PTEN loss were identified as independent risk factors for PFS. PTEN loss was identified as an independent risk factor for OS.
  
  
  CONCLUSIONS
  HER3 and PTEN expressions may be predictive markers, and PTEN expression may be a predictive and prognostic biomarker for trastuzumab treatment in HER2-positive MBCs.
authors.affiliation: Division of Hematology-Oncology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Y H
authors.initials: YH
authors.lastname: Park
authors.affiliation: Division of Hematology-Oncology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: H A
authors.initials: HA
authors.lastname: Jung
authors.affiliation: Division of Hematology-Oncology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: M K
authors.initials: MK
authors.lastname: Choi
authors.affiliation: Division of Hematology-Oncology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: W
authors.initials: W
authors.lastname: Chang
authors.affiliation: Department of Pathology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Y L
authors.initials: YL
authors.lastname: Choi
authors.affiliation: Department of Pathology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: I-g
authors.initials: IG
authors.lastname: Do
authors.affiliation: Division of Hematology-Oncology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: J S
authors.initials: JS
authors.lastname: Ahn
authors.affiliation: Division of Hematology-Oncology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Y-H
authors.initials: YH
authors.lastname: Im
mesh_terms: D000328:Adult; D000368:Aged; D061067:Antibodies, Monoclonal, Humanized / Q000008:administration & dosage; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000201:enzymology* / Q000235:genetics; D001952:Bridged-Ring Compounds / Q000008:administration & dosage; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008875:Middle Aged; D051059:PTEN Phosphohydrolase / Q000172:deficiency* / Q000235:genetics; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics*; D020893:Receptor, ErbB-3 / Q000096:biosynthesis* / Q000235:genetics; D012189:Retrospective Studies; D043823:Taxoids / Q000008:administration & dosage; D000068878:Trastuzumab
chemical_list: D061067:Antibodies, Monoclonal, Humanized; D001952:Bridged-Ring Compounds; D051059:PTEN Phosphohydrolase; D018719:Erb-b2 Receptor Tyrosine Kinases; D020893:Receptor, ErbB-3; D043823:Taxoids; D000068878:Trastuzumab; C080625:taxane; C581292:ERBB3 protein, human; C494929:PTEN protein, human