The DNA methylation of the interleukin6 as a biomarker for the early detection of colorectal cancer

Objectives: To identify the DNA methylation pattern of the interleukin6 promoter region in colorectal cancer patients and colorectal polys patients that could be a biomarker for early detection of colorectal cancer. Methods: For this purpose, we examined the DNA methylation pattern of the promoter region of the IL6 specifically 358 bp (-292 to +67) including 7 CpG sites (-228, -213, -163, -119, +10, +19, +25) in a total of ninety samples with thirty samples each for controls, cancer patients, and colorectal polyps using the bisulfite conversion sequencing method. Result: Our results indicate that CpG +25 and CpG -119 can serve as biomarkers for early detection of colon cancer, showing a significant difference in P-values of 0.001 at CpG +25 and 0.004 at CpG-119. The hypomethylation of CpG -119 in cancer groups facilitates the binding of the methyl-sensitive transcription factor Sp1. It enhances the overexpression of IL6 besides hypermethylation of CpG +25 that prevents binding of the methyl-sensitive insulator CTF, unbinding the insulator to the promoter region of the cancer samples makes the promoter region open access to the TFs that enhances overexpression. Furthermore, a remarkable non-recorded SNP at CpG -228 was observed in 98.6% of the enrolled groups. Conclusion: In the state of DNA methylation, IL 6 could contribute to the onset of colorectal polyps and colorectal polyps cancer due to a significant level of methylation in CpG +25 and CpG -119.