title: BRCAness is beneficial for indicating triple negative breast cancer patients resistant to taxane.
abstract: Triple negative breast cancer (TNBC) is a heterogeneous disease and is associated with the cancer stem cell (CSC), basal-like, and BRCA1 function deficient (BRCAness) subtypes. We examined these 3 subtypes in TNBC and compared their chemosensitivity against anthracycline or taxane with a special attention to BRCAness.
  
  
  
  Sixty-six TNBC cases were obtained from a randomized phase II trial comparing TCx6 (TC6) with FEC-Docetaxel (FEC-D) as neoadjuvant chemotherapy. The core needle specimens before chemotherapy were used for subtyping. The basal-like and CSC subtypes were identified by immunohistochemistry; CK5/6 and EGFR staining for the basal-like subtype and ALDH1 staining for the CSC subtype. The BRCAness subtype was examined by Multiplex Ligation-dependent Probe Amplification (MLPA). Correlations between subgroups and pCR rates according to each regimen and subtype were examined.
  
  
  
  The basal-like and BRCAness subtypes were significantly associated (p = 0.010) with the other subtypes, but not the CSC subtype. The pCR rates were higher with FEC-D than with TC6 in the basal-like (54.5% vs 14.3%, p = 0.081) and BRCAness (56.2% vs 16.7%, p = 0.030) subtypes. Both were not effective in the CSC subtype (18.2% vs 11.8%, p = 1.00).
  
  
  
  BRCAness identified by MLPA was practically useful for treatment selection for avoiding taxane. ALDH1 may be considered as a marker for the CSC subtype requiring novel agents.
authors.affiliation: Department of Breast Surgery, Tokyo Medical University, 6-7-1 Nishishinjuku, Shinjuku, Tokyo 160-0023, Japan. Electronic address: tishik55@gmail.com.
authors.forename: T
authors.initials: T
authors.lastname: Ishikawa
authors.affiliation: Department of Breast and Thyroid Surgery, Yokohama City University Medical Center, Yokohama 232-0024, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Narui
authors.affiliation: Department of Pathology, Yokohama City University Medical Center, Yokohama 232-0024, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Tanabe
authors.affiliation: Department of Breast and Thyroid Surgery, Yokohama City University Medical Center, Yokohama 232-0024, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Kida
authors.affiliation: Department of Bioinformatics, Yokohama City University Medical Center, Yokohama 232-0024, Japan.
authors.forename: M S
authors.initials: MS
authors.lastname: Oba
authors.affiliation: Department of Breast and Thyroid Surgery, Yokohama City University Medical Center, Yokohama 232-0024, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Yamada
authors.affiliation: Department of Clinical Oncology and Gastrointestinal Surgery, School of Medicine, Yokohama City University, Yokohama 232-0024, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Ichikawa
authors.affiliation: Department of Clinical Oncology and Gastrointestinal Surgery, School of Medicine, Yokohama City University, Yokohama 232-0024, Japan.
authors.forename: I
authors.initials: I
authors.lastname: Endo
mesh_terms: D000328:Adult; D000368:Aged; D018943:Anthracyclines / Q000008:administration & dosage; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage / Q000627:therapeutic use*; D019313:BRCA1 Protein / Q000378:metabolism*; D001952:Bridged-Ring Compounds / Q000008:administration & dosage; D003520:Cyclophosphamide / Q000008:administration & dosage; D004334:Drug Administration Schedule; D019008:Drug Resistance, Neoplasm; D015251:Epirubicin / Q000008:administration & dosage; D005260:Female; D005472:Fluorouracil / Q000008:administration & dosage; D006801:Humans; D007150:Immunohistochemistry; D008875:Middle Aged; D060885:Multiplex Polymerase Chain Reaction; D043823:Taxoids / Q000008:administration & dosage; D016896:Treatment Outcome; D064726:Triple Negative Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology*
chemical_list: D018943:Anthracyclines; D019313:BRCA1 Protein; C492913:BRCA1 protein, human; D001952:Bridged-Ring Compounds; D043823:Taxoids; C080625:taxane; D015251:Epirubicin; D003520:Cyclophosphamide; D005472:Fluorouracil
keywords: BRCAness; Basal-like; Breast cancer; Cancer stem cell; Triple negative