Abstract:

Aim: Colorectal cancer, the most widely seen type of cancer of the gastrointestinal system, is also the fourth most common cause of death among cancer diseases. Early diagnosis of this type of cancer is important for prognosis and it is reported that the use of inflammatory cytokines in circulation might be useful as a prognostic biomarker. For this purpose, in this study, association of interleukin-6 (IL-6)-174 G/C and interleukin-18 (IL-18) -607 C/A polymorphisms and plasma levels with colorectal cancer was investigated. Method: This study was consist of 96 patients with colorectal cancer and 96 healthy individuals as control group. The polymorphisms of the patients and healthy volunteers groups were investigated by Real-Time PCR. The plasma levels of IL-6 and IL-18 were determined by ELISA method. Results: Upon comparison of the genotype rates of IL-6 G/C (rs1800795) and IL-18 C/A (rs1946518) polymorphisms, a statistically significant difference was found between the patient and the control groups (p<0.001). Plasma levels of IL-6 were significantly higher in the group of patients with colorectal cancer (p<0.001). However, no statistically significant difference was found among the plasma levels of IL-18 in the control group (p<0.966). In order to determine the likelihood of developing CRC due to the combined effects of IL-6 and IL-18 genotypes, the association of genotype combinations of both genes in patients and control group with CRC development was investigated. In such cases that GC- CA and CC-CA genotype combinations exist and both genes are heterozygous, it was determined that there might be a risk of CRC development. Conclusion: Interleukin-6 and interleukin-18 may play a role in the development of colorectal cancer. In addition, the plasma levels of these cytokines can be used for early diagnosis

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