title: BCL2 as a Subtype-Specific Prognostic Marker for Breast Cancer.
abstract: OBJECTIVE
  B-cell lymphoma 2 (BCL2) is an antiapoptosis protein and an important clinical breast cancer prognostic marker. As the role of BCL2 is dependent on the estrogen receptor (ER) status, this effect might differ according to molecular subtypes. The aim of this study was to evaluate the relationship between the prognostic outcomes and BCL2 expression among the molecular subtypes.
  
  
  METHODS
  We retrieved the data of 1,356 patients who were newly diagnosed with malignant breast cancer between November 2006 and November 2011. Immunohistochemistry was used to measure ER, progesterone receptor, human epidermal growth factor receptor 2 (HER2), Ki-67, and BCL2 expression. We classified breast cancer into five molecular subtypes based on the 13th St. Gallen International Expert Consensus, including luminal A, luminal B (HER2-negative), luminal B (HER2-positive), HER2-overexpression, and triple-negative subtypes. We analyzed the clinicopathological features and assessed the correlation between BCL2 expression and clinical outcomes, such as relapse-free survival (RFS) and disease-specific survival (DSS) according to the five molecular subtypes.
  
  
  RESULTS
  A total of 605 cases of breast cancer (53.8%) showed BCL2 expression. BCL2-positive expression was associated with young age (<50 years,p=0.036), lower histological grade (p<0.001), low Ki-67 level (<14%,p<0.001), hormone receptor positivity (p<0.001), HER2 negativity (p<0.001), luminal breast cancer (p<0.001), and low recurrence rate (p=0.016). BCL2-positive expression was also associated with favorable 5-year RFS (p=0.008, 91.4%) and DSS (p=0.036, 95.6%) in all the patients. BCL2-positive expression in luminal A breast cancer resulted in significantly favorable 5-year RFS and DSS (p=0.023 andp=0.041, respectively). However, BCL2 expression was not associated with the prognosis in the other subtypes.
  
  
  CONCLUSIONS
  The prognostic role of BCL2 expression in breast cancer is subtype-specific. BCL2 expression differs according to the molecular subtype and is a good prognostic marker for only luminal A breast cancer.
authors.affiliation: Department of Surgery, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Yong Hwa
authors.initials: YH
authors.lastname: Eom
authors.affiliation: Department of Surgery, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Hyung Suk
authors.initials: HS
authors.lastname: Kim
authors.affiliation: Department of Pathology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Ahwon
authors.initials: A
authors.lastname: Lee
authors.affiliation: Department of Surgery, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.; Cancer Research Institute, The Catholic University of Korea, Seoul, Korea.
authors.forename: Byung Joo
authors.initials: BJ
authors.lastname: Song
authors.affiliation: Department of Surgery, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.; Cancer Research Institute, The Catholic University of Korea, Seoul, Korea.
authors.forename: Byung Joo
authors.initials: BJ
authors.lastname: Chae
keywords: B-cell lymphoma 2 protein; Breast neoplasms; Prognosis; Tumor biomarkers