title: Prognostic and clinicopathological significance of serum interleukin-6 expression in colorectal cancer: a systematic review and meta-analysis.
abstract: OBJECTIVE
  Interleukin-6 (IL-6) plays an important role in human colorectal cancer (CRC) development. However, the exact clinical and prognostic significance of IL-6 in CRC is still unclear. Here, we conducted this meta-analysis to explore this issue in detail.
  
  
  METHODS
  A meta-analysis was performed to clarify the association between serum IL-6 expression and clinical outcomes in articles published up to June 2015. Weighted mean difference (WMD) and its corresponding 95% confidence interval (CI) were used to assess the association between serum IL-6 expression and the clinicopathological characteristics of CRC. Hazard ratio (HR) with 95% CI was used to quantify the predictive value of IL-6 on CRC prognosis.
  
  
  RESULTS
  Fourteen studies comprising 1,245 patients were included. Analysis of these data showed that serum IL-6 expression was highly correlated with poor 5-year overall survival (OS) rate (HR =0.43, 95% CI: 0.31-0.59, P=0.755). Simultaneously, we also found that serum IL-6 expression was associated with certain clinical parameters of CRC, such as tumor invasion (T category: T0-T2, T3-T4) (WMD =3.15, 95% CI: 1.92-4.39, P=0.816), distant metastasis (M category: M0, M1) (WMD =4.69, 95% CI: 3.33-6.06, P=0.377), and tumor stage (I-II, III-IV) (WMD =2.65, 95% CI: 1.09-4.21, P=0.066).
  
  
  CONCLUSIONS
  A high serum IL-6 expression is associated with adverse OS in CRC. The IL-6 expression can be an important supplement in establishing prognostic score for clinical decision.
authors.affiliation: Cancer Institute, Key Laboratory of Cancer Prevention and Intervention, Key Laboratory of Molecular Biology in Medical Sciences, China National Ministry of Education.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Cancer Institute, Key Laboratory of Cancer Prevention and Intervention, Key Laboratory of Molecular Biology in Medical Sciences, China National Ministry of Education ; Department of Thoracic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Zhejiang University, Hangzhou, Zhejiang Province, People's Republic of China.
authors.forename: Pin
authors.initials: P
authors.lastname: Wu
authors.affiliation: Cancer Institute, Key Laboratory of Cancer Prevention and Intervention, Key Laboratory of Molecular Biology in Medical Sciences, China National Ministry of Education.
authors.forename: Dang
authors.initials: D
authors.lastname: Wu
authors.affiliation: Department of Gynecology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Zhejiang University, Hangzhou, Zhejiang Province, People's Republic of China.
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Cancer Institute, Key Laboratory of Cancer Prevention and Intervention, Key Laboratory of Molecular Biology in Medical Sciences, China National Ministry of Education.
authors.forename: Guoming
authors.initials: G
authors.lastname: Hu
authors.affiliation: Cancer Institute, Key Laboratory of Cancer Prevention and Intervention, Key Laboratory of Molecular Biology in Medical Sciences, China National Ministry of Education.
authors.forename: Shuai
authors.initials: S
authors.lastname: Zhao
authors.affiliation: Cancer Institute, Key Laboratory of Cancer Prevention and Intervention, Key Laboratory of Molecular Biology in Medical Sciences, China National Ministry of Education.
authors.forename: Yucheng
authors.initials: Y
authors.lastname: Lai
authors.affiliation: Cancer Institute, Key Laboratory of Cancer Prevention and Intervention, Key Laboratory of Molecular Biology in Medical Sciences, China National Ministry of Education ; Department of Surgical Oncology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Zhejiang University, Hangzhou, Zhejiang Province, People's Republic of China.
authors.forename: Jian
authors.initials: J
authors.lastname: Huang
keywords: colorectal cancer; interleukin-6; meta-analysis; prognosis