C-reactive protein, interleukin-6 and the risk of colorectal cancer: a meta-analysis

Cancer Causes Control. 2014 Oct;25(10):1397-405. doi: 10.1007/s10552-014-0445-8. Epub 2014 Jul 23.


Purpose: Many studies have evaluated the associations between pre-diagnostic circulating C-reactive protein (CRP), interleukin-6 (IL-6) and colorectal cancer risk, but their results are inconsistent. We therefore conducted a meta-analysis to investigate these associations.

Methods: A comprehensive literature search up to October 2013 was undertaken in PubMed. Pooled relative risk (RR) estimates and 95% confidence intervals (CIs) were used to calculate estimated effect.

Results: Eighteen studies on CRP comprising a total of 4,706 colorectal cancer cases were included in this meta-analysis. The summary RR of colorectal cancer for one unit change in natural logarithm (ln) CRP was 1.12 [95% CI (1.05-1.21)]. There was statistically significant heterogeneity among studies (p = 0.006; I (2) = 51.7%). After excluding the studies contributing most to the heterogeneity, summary estimate was essentially unchanged. In addition, the association was significant for colon cancer [RR = 1.13, 95 % CI (1.05-1.21)], not for rectal cancer [RR = 1.03, 95% CI (0.90-1.17)]. We also found that CRP was significantly associated with increased risk of colorectal cancer among men, but not among women. There were six studies on IL-6 that involved a total of 1,068 colorectal cancer cases. The pooled RR of colorectal cancer for one unit change in ln IL-6 was 1.10 (95% CI 0.88-1.36), and no statistically significant heterogeneity was found (p = 0.175; I(2) = 34.8%).

Conclusion: Our results suggest that pre-diagnostic circulating CRP is associated with increased risk of colorectal cancer. However, there is no significant association between IL-6 and colorectal cancer risk.

Publication types

  • Meta-Analysis
  • Review

MeSH terms

  • Biomarkers, Tumor / blood*
  • C-Reactive Protein / metabolism*
  • Case-Control Studies
  • Colonic Neoplasms / blood
  • Colonic Neoplasms / diagnosis
  • Colonic Neoplasms / epidemiology
  • Colorectal Neoplasms / blood*
  • Colorectal Neoplasms / diagnosis*
  • Colorectal Neoplasms / epidemiology
  • Confidence Intervals
  • Early Detection of Cancer
  • Female
  • Humans
  • Incidence
  • Interleukin-6 / blood*
  • Male
  • Rectal Neoplasms / blood
  • Rectal Neoplasms / diagnosis
  • Rectal Neoplasms / epidemiology
  • Risk Assessment
  • Risk Factors


  • Biomarkers, Tumor
  • IL6 protein, human
  • Interleukin-6
  • C-Reactive Protein