title: Cancer stem cell marker Bmi-1 expression is associated with basal-like phenotype and poor survival in breast cancer.
abstract: BACKGROUND
  The purpose of present study was to examine the expression of cancer stem cell marker Bmi-1 in breast cancer tissue and to evaluate the clinical implication of Bmi-1 expression for these patients.
  
  
  METHODS
  A total of 171 breast cancer patients who received surgical treatment in our hospital were enrolled in this study. Bmi-1 expression in breast cancer tissue was assayed by immunohistochemistry. Statistical analyses were applied to test the relationship between expression of Bmi-1 and clinicopathologic features and patient survival. The relationship between Bmi-1 and the basal-like phenotype of breast cancer also was analyzed in this study.
  
  
  RESULTS
  Positive Bmi-1 expression was detected in 89 of 171 (52%) invasive breast cancers patients. The Bmi-1 status was significantly correlated to histological grade III (p = 0.001) and basal-like phenotype (p < 0.001). The 5 year overall survival of the patients with Bmi-1-positive and -negative cancers were 78 and 91.9%, respectively (p = 0.03). Histological grade (p = 0.046) and Bmi-1 status (p = 0.012) were detected as the independent prognostic factors in the Cox regression test.
  
  
  CONCLUSIONS
  Bmi-1 status is an independent prognostic factor, which also is associated with tumor histological grade and basal-like phenotype. The high proportions of positive Bmi-1 expression in basal-like breast cancer may be related to the high aggressiveness behavior of this subtype of breast cancer.
authors.affiliation: Department of Radiation Oncology, General Hospital of Ningxia Medical University, Yinchuan, No. 804 Shengli Str, Yinchuan, 750004, Ningxia, China. fdwyy1981@hotmail.com.
authors.forename: Yanyang
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Radiation Oncology, General Hospital of Ningxia Medical University, Yinchuan, No. 804 Shengli Str, Yinchuan, 750004, Ningxia, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Zhe
authors.affiliation: Department of Radiation Oncology, General Hospital of Ningxia Medical University, Yinchuan, No. 804 Shengli Str, Yinchuan, 750004, Ningxia, China.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Ding
authors.affiliation: Department of Surgical Oncology, General Hospital of Ningxia Medical University, Yinchuan, Ningxia, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Gao
authors.affiliation: Department of Pathology, General Hospital of Ningxia Medical University, Yinchuan, Ningxia, China.
authors.forename: Ningmei
authors.initials: N
authors.lastname: Zhang
authors.affiliation: Department of Pathology, General Hospital of Ningxia Medical University, Yinchuan, Ningxia, China.
authors.forename: Guofu
authors.initials: G
authors.lastname: Li
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism*; D001943:Breast Neoplasms / Q000378:metabolism* / Q000401:mortality / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000378:metabolism* / Q000401:mortality / Q000473:pathology; D018275:Carcinoma, Lobular / Q000378:metabolism* / Q000401:mortality / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D060787:Neoplasm Grading; D009687:Nuclear Proteins / Q000378:metabolism*; D010641:Phenotype; D063150:Polycomb Repressive Complex 1; D011379:Prognosis; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D012097:Repressor Proteins / Q000378:metabolism*; D016019:Survival Analysis
chemical_list: C069077:BMI1 protein, human; D014408:Biomarkers, Tumor; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D012097:Repressor Proteins; D063150:Polycomb Repressive Complex 1