Investigating the methylation status of gene and its association with C677T polymorphism in patients with colorectal cancer.

Colorectal cancer (CRC) is one of the common causes of cancer death in Iranian population. Both genetic and epigenetic changes have been implicated in CRC pathogenesis. gene as one of the WNT signaling pathway inhibitor was shown to display tumor suppressor activity in many cancers. The aim of present study was to investigate the methylation status of gene and its association with methylenetetrahydrofolate reductase () C677T polymorphism in CRC patients. Fifty formalin-fixed paraffin-embedded cancerous and adjacent healthy tissues obtained from CRC patient were investigated. Genomic DNA was isolated using a FFPE commercial DNA extraction kit. The methylation status was evaluated by methylation specific PCR. Genotyping of C677T polymorphism was performed using PCR-RFLP technique. Statistical analysis was done by GraphPad Prism 8. Results indicated that the frequency of methylated gene was significantly higher in cancerous tissue relative to adjacent healthy tissue (P<0.001). gene methylation was significantly more common among carriers of 677CC genotype (P=0.035) and significantly less common among carriers of 677T allele (P value =0.006). In conclusion the present study identified gene methylation as a significant risk factor for CRC development. Moreover, the low frequency of gene methylation among carriers of 677T allele may confer a protective role for this common polymorphism against CRC risk.