BRCAness is beneficial for indicating triple negative breast cancer patients resistant to taxane

• Published in: European journal of surgical oncology 2016-07, Vol.42 (7), p.999-1001
• Main Authors: Ishikawa, Takashi, MD, PhD, Narui, Kazutaka, Tanabe, Mikiko, Kida, Kumiko, Oba, Mari S, Yamada, Akimitsu, Ichikawa, Yasushi, Endo, Itaru
• Format: Article
• Language: English
• Subjects: Adult; Aged; Anthracyclines - administration & dosage; Antineoplastic Combined Chemotherapy Protocols - administration & dosage; Antineoplastic Combined Chemotherapy Protocols - therapeutic use; Basal-like; BRCA1 Protein - metabolism; BRCAness; Breast cancer; Bridged-Ring Compounds - administration & dosage; Cancer stem cell; Cyclophosphamide - administration & dosage; Drug Administration Schedule; Drug Resistance, Neoplasm; Epirubicin - administration & dosage; Female; Fluorouracil - administration & dosage; Hematology, Oncology and Palliative Medicine; Humans; Immunohistochemistry; Middle Aged; Multiplex Polymerase Chain Reaction; Surgery; Taxoids - administration & dosage; Treatment Outcome; Triple negative; Triple Negative Breast Neoplasms - drug therapy; Triple Negative Breast Neoplasms - metabolism; Triple Negative Breast Neoplasms - pathology
• ISSN: 0748-7983; 1532-2157
• DOI: 10.1016/j.ejso.2016.02.246

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.