title: Triple-negative, basal-like, and quintuple-negative breast cancers: better prediction model for survival.
abstract: BACKGROUND
  Triple-negative breast cancers (TNBCs) and basal-like breast cancers (BLBCs) are known as poor outcome subtypes with a lack of targeted therapy. Previous studies have shown conflicting results regarding the difference of prognostic significance between TNBCs and BLBCs. In this study, we aimed to characterize the prognostic features of TNBCs, in view of BLBCs and quintuple-negative breast cancers (QNBC/5NPs).
  
  
  METHODS
  Using tissue microarray-based immunohistochemical analysis, we categorized 951 primary breast cancers into four or five subtypes according to the expression of ER, PR, HER2, and basal markers (CK5/6, EGFR).
  
  
  RESULTS
  The results of this study showed that both TNBCs and BLBCs were associated with high histological and/or nuclear grades. When the TNBCs are divided into two subtypes by the presence of basal markers, the clinicopathologic characteristics of TNBCs were mainly maintained in the BLBCs. The 5-subgrouping was the better prediction model for both disease free and overall survival in breast cancers than the 4-subgrouping. After multivariate analysis of TNBCs, the BLBCs did not have a worse prognosis than the QNBC/5NPs. Interestingly, the patients with BLBCs showed significant adjuvant chemotherapy benefit. In addition, QNBC/5NPs comprised about 6~8% of breast cancers in publicly available breast cancer datasets
  
  
  CONCLUSIONS
  The QNBC/5NP subtype is a worse prognostic subgroup of TNBCs, especially in higher stage and this result may be related to adjuvant chemotherapy benefit of BLBCs, calling for caution in the identification of subgroups of patients for therapeutic classification.
authors.affiliation: Laboratory of Cancer Genomics and Molecular Pathology, Samsung Medical Center, Seoul, Korea.
authors.forename: Yoon-La
authors.initials: YL
authors.lastname: Choi
authors.forename: Ensel
authors.initials: E
authors.lastname: Oh
authors.forename: Sarah
authors.initials: S
authors.lastname: Park
authors.forename: Yeonju
authors.initials: Y
authors.lastname: Kim
authors.forename: Yeon-Hee
authors.initials: YH
authors.lastname: Park
authors.forename: Kyoung
authors.initials: K
authors.lastname: Song
authors.forename: Eun Yoon
authors.initials: EY
authors.lastname: Cho
authors.forename: Yun-Chul
authors.initials: YC
authors.lastname: Hong
authors.forename: Jong Sun
authors.initials: JS
authors.lastname: Choi
authors.forename: Jeong Eon
authors.initials: JE
authors.lastname: Lee
authors.forename: Jung Han
authors.initials: JH
authors.lastname: Kim
authors.forename: Seok Jin
authors.initials: SJ
authors.lastname: Nam
authors.forename: Young-Hyuck
authors.initials: YH
authors.lastname: Im
authors.forename: Jung-Hyun
authors.initials: JH
authors.lastname: Yang
authors.forename: Young Kee
authors.initials: YK
authors.lastname: Shin
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000378:metabolism* / Q000401:mortality*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D017404:In Situ Hybridization, Fluorescence; D008495:Medical Oncology / Q000379:methods; D008875:Middle Aged; D015999:Multivariate Analysis; D020411:Oligonucleotide Array Sequence Analysis; D011379:Prognosis; D016896:Treatment Outcome