TFPI2 and NDRG4 gene promoter methylation analysis in peripheral blood mononuclear cells are novel epigenetic noninvasive biomarkers for colorectal cancer diagnosis

Background and Objective:Due to the growing prevalence of colorectal cancer (CRC), new screening and early detection methods are demanded. Among novel biomarkers, DNA methylation emerged as high potential diagnosis/screening molecular marker. The objective of this study was to assess non-invasive early diagnosis of CRC by examining promoter methylation of TFPI2 and NDRG4 genes in peripheral blood mononuclear cells (PBMC). Materials and Methods: Fifty CRC patients and 50 normal controls were recruited to this study. Quantitative methylation of promoter region of TFPI2 and NDRG4 genes were analyzed in DNA extracted from PBMC of all cases and control subjects using methylation-quantification endonuclease-resistant DNA (MethyQESD) method. Findings: The sensitivity and specificity of TFPI2 gene for diagnosis of CRC was 88% and 92%, respectively and for NDRG4 gene was 86% and 92% respectively. Methylation range for TFPI2 gene was 43.93% and 11.56% in patients and controls respectively, and for NDRG4 gene was 38.8% in CRC patients and 12.23% in healthy controls (P < 0.001). Also we observed that the higher percentage of methylation correlated with the higher stage of CRC. Conclusion: Based on our results it is revealed that PBMCs are reliable sources of methylation analysis for CRC screening. Also TFPI2 and NDRG4 genes are providing high enough sensitivity and specificity to be nominated as novel noninvasive CRC screening in PBMCs.

Keywords:

Colorectal cancer , Quantitative methylation analysis , PBMC , NDRG4 , TFPI2.