title: Interleukin-6 as a prognostic marker for breast cancer: a meta-analysis.
abstract: OBJECTIVE
  Interleukin-6 (IL-6) has been shown to promote tumor survival, metastasis, and angiogenesis, in addition to possessing antitumor activities. In light of the conflicting data, we sought to determine whether IL-6 could be used as a prognostic factor for patients with breast cancer.
  
  
  METHODS
  Eligible studies describing the use of IL-6 as a prognostic factor for breast cancer were identified. Data describing overall survival (OS), disease-free survival (DFS), and clinicopathologic features were collected and analyzed.
  
  
  RESULTS
  Thirteen articles containing 3,224 breast cancer patients were identified. The results showed that IL-6 expression was not associated with lymph node metastasis, tumor size, or histologic grade. Moreover, there was no correlation between IL-6 expression and DFS. However, the combined hazard ratio (95% confidence interval) for OS was 2.15 (1.46, 3.17). Sensitivity analysis further demonstrated that, for OS, the results of this meta-analysis were stable. A subgroup analysis showed that the source used to detect IL-6 levels may have altered the pooled results for OS.
  
  
  CONCLUSIONS
  Taken together, these results indicate that IL-6 expression is associated with poor prognosis for breast cancer and the prognostic role is affected by the source used to detect IL-6 levels.
authors.affiliation: Department of Oncology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai - People's Republic of China.
authors.forename: ShuChen
authors.initials: S
authors.lastname: Lin
authors.forename: ZhiHua
authors.initials: Z
authors.lastname: Gan
authors.forename: Kun
authors.initials: K
authors.lastname: Han
authors.forename: Yang
authors.initials: Y
authors.lastname: Yao
authors.forename: DaLiu
authors.initials: D
authors.lastname: Min
mesh_terms: D014408:Biomarkers, Tumor / Q000097:blood*; D001943:Breast Neoplasms / Q000097:blood* / Q000401:mortality / Q000473:pathology*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D015850:Interleukin-6 / Q000097:blood*; D060787:Neoplasm Grading; D011237:Predictive Value of Tests; D011379:Prognosis; D016019:Survival Analysis
chemical_list: D014408:Biomarkers, Tumor; D015850:Interleukin-6