Clinical significance of serum interleukin-17 levels in colorectal cancer patients.

Purpose: The proinflammatory cytokine, interleukin-17 (IL-17) plays a potent role in T-cell mediated angiogenesis and promotes tumorigenicity. The objective of this study was to determine the clinical outcomes of colorectal cancer (CRC) patients in relation to serum IL-17 levels.

Methods: Ninety-six CRC patients were enrolled in this study. Pre-treatment serum IL-17 levels were determined by enzyme- linked immunosorbent assay (ELISA). Thirty age - and sex-matched healthy controls were included in the analysis.

Results: The median patient age was 60 years (range: 24-84) and the most frequent localization was colon (N=59;61%). Median follow-up time was 14 months, 27 patients (28%) experienced disease progression, and 20 of the remaining patients (20%) died. The estimated and 1-year progression-free survival (PFS) and 2-year overall survival (OS) rates for the whole patient group were 26.9% (95% confidence interval [CI]=9.9-44.0) and 71% (95% CI=56.0- 85.0), respectively. The number of patients who received neoadjuvant treatment was 25. Of the patients who received palliative treatment, 11 had oxaliplatin whereas 18 and 7 had irinotecan and FU/capecitabine, chemotherapy (CTx). Twenty-four and nine of the patients who received targeted therapy had bevacizumab and cetuximab, respectively. Thirty-three percent of 36 metastatic patients who received palliative CTx were CTx-responsive. The baseline median serum IL-17 levels were significantly lower in patients with CRC than in the healthy control group (p=0.01). Moreover, known clinical variables including older age, poor grade and low albumin levels were found to be correlated with high serum IL-17 concentrations (p=0.02, p=0.02, and p=0.04, respectively). No statistically significant serum IL- 17 concentrations were noted regarding PFS and OS.

Conclusion: Serum levels of IL-17 may be diagnostic marker in CRC patients. However, no predictive and prognostic values were determined.