Breast Cancer Research and Treatment

, Volume 113, Issue 1, pp 83–93

Expression of Bmi-1 protein in tumor tissues is associated with favorable prognosis in breast cancer patients

  • Young Jin Choi
  • Yoon La Choi
  • Eun Yoon Cho
  • Young Kee Shin
  • Ki Woong Sung
  • Yu Kyeong Hwang
  • Sang Jin Lee
  • Gu Kong
  • Jeong Eon Lee
  • Jee Soo Kim
  • Jung Han Kim
  • Jung-Hyun Yang
  • Seok Jin Nam
Preclinical Study

Abstract

Purpose Abnormal expression of the cell cycle regulatory protein Bmi-1 has been studied in breast cancer, but the clinical relevance has not been fully elucidated. We studied the expression of Bmi-1 protein in breast cancer patients to define its clinical significance in breast cancer. Experimental Design Tissue microarrays were performed to evaluate the expression of Bmi-1 by immunohistochemistry in tumor tissues from 960 patients with stage I–III breast cancer. We assessed the relationship between the expression of Bmi-1 and pathologic prognostic indices as well as clinical long-term follow up outcome. Results Bmi-1 was expressed in 53.2% of breast cancer patients by immunohistochemistry, and the expression of Bmi-1 was significantly correlated with favorable prognostic indices at diagnosis. In univariate analysis, patients with Bmi-1 expression showed favorable relapse-free survival (88.6 ± 2.7% vs. 72.3 ± 4.3%, P = 0.041) and favorable overall survival (93.5 ± 2.2% vs. 82.6 ± 3.5%, P < 0.001) than patients without Bmi-1 expression. According to multivariate analyses, Bmi-1 expression was identified as independent prognostic factor for overall survival with a statistical significance (hazard ratio of Bmi-1 (−) patients compared to Bmi-1 (+) patients, 1.744; 95% CI, 1.013–3.003; P = 0.045). This correlation of Bmi-1 expression with favorable overall survival was maintained in patients underwent uniform chemotherapy, regardless of undergoing adjuvant chemotherapy. In a subset analysis according to ER status, Bmi-1 expression associated with favorable overall survival only in ER-positive patients. Conclusions Bmi-1 expression assessed with Immunohistochemistry may be associated with favorable overall survival in breast cancer patients, especially in patients with ER-positive breast cancer.

Keywords

Bmi-1 Breast cancer Cell cycle regulator Immunohistochemistry Prognostic markers 

Copyright information

© Springer Science+Business Media, LLC. 2008

Authors and Affiliations

  • Young Jin Choi
    • 1
  • Yoon La Choi
    • 2
  • Eun Yoon Cho
    • 2
  • Young Kee Shin
    • 3
  • Ki Woong Sung
    • 4
  • Yu Kyeong Hwang
    • 5
  • Sang Jin Lee
    • 6
  • Gu Kong
    • 7
  • Jeong Eon Lee
    • 1
  • Jee Soo Kim
    • 1
  • Jung Han Kim
    • 1
  • Jung-Hyun Yang
    • 1
  • Seok Jin Nam
    • 1
  1. 1.Department of Surgery Samsung Medical Center, Sungkyunkwan University School of MedicineSeoulKorea
  2. 2.Department of PathologySamsung Medical Center, Sungkyunkwan University School of MedicineSeoulKorea
  3. 3.Research Institute of Pharmaceutical Science, Department of PharmacySeoul National University College of PharmacySeoulKorea
  4. 4.Department of PediatricsSamsung Medical Center, Sungkyunkwan University School of MedicineSeoulKorea
  5. 5.Division of ImmunotherapyMogam Biotechnology Research InstituteYonginKorea
  6. 6.Genitourinary Cancer BranchNational Cancer CenterIlsanKorea
  7. 7.Department of Pathology, College of MedicineHanyang UniversitySeoulKorea

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