Serum interleukin-6 level reflects the tumor proliferative activity in patients with colorectal carcinoma

Cancer. 1999 Jun 15;85(12):2526-31. doi: 10.1002/(sici)1097-0142(19990615)85:12<2526::aid-cncr6>;2-3.


Background: Interleukin (IL)-6 plays a central role as a differentiation and growth factor of tumor cells. It may be hypothesized that increased serum IL-6 derives from the tumor tissue, and that serum IL-6 levels consequently reflect the biologic characteristics of the tumor. The authors investigated the association between the serum levels of IL-6 in colorectal carcinoma patients and the biologic characteristics of the tumor as well as clinicopathologic status of the patients.

Methods: Serum and tissue levels of IL-6 in 70 patients were determined using an immunoradiometric assay. Expression of IL-6 and IL-6 receptor were evaluated immunohistochemically. The proliferative activity of the tumor was assessed by nuclear Ki-67 labeling index.

Results: The concentration of serum IL-6 in the patients was significantly higher than that in normal controls. The tissue concentration of IL-6 in tumor tissue was significantly higher than that in normal mucosa, and was correlated strongly with the serum IL-6 concentration. The serum IL-6 concentration was correlated with clinicopathologic parameters, including liver metastases and tumor size, and with proliferative activity of the tumor as assessed by the Ki-67 labeling index. In the patients with Stage I or II tumors, the preoperative serum IL-6 concentration was reduced significantly 3 months after surgery. Immunohistochemically, tumor tissues that expressed IL-6 immunoreactivity had a higher incidence of expression of IL-6 receptor immunoreactivity. CONCLUSIONS. Serum IL-6 concentration reflects IL-6 concentration in the tumor component and may reflect the proliferative activity of the tumor in patients with colorectal carcinoma.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Biomarkers, Tumor / blood*
  • Carcinoma / pathology*
  • Cell Division
  • Colorectal Neoplasms / pathology*
  • Female
  • Humans
  • Interleukin-6 / blood*
  • Male
  • Middle Aged
  • Neoplasm Staging / methods
  • Predictive Value of Tests


  • Biomarkers, Tumor
  • Interleukin-6