Allele and Genotype Frequencies of the Polymorphic Methylenetetrahydrofolate Reductase and Colorectal Cancer among Jordanian Population

Background: Methylenetetrahydrofolate reductase (MTHFR) is involved in DNA synthesis and repair. We hereaimed to investigate two common polymorphisms, C677T and A1298C, with genotype and haplotype frequenciesin colorectal cancer (CRC) cases among Jordanian. Materials and
Methods: 131 CRC cases were studied forMTHFR C677T and A1298C polymorphisms, compared to 117 controls taken from the general population,employing the PCR-RFLP technique.
Results: We found the frequency of the three different genotypes of MTHFRC677T among Jordanians to be CC: 61.7%, CT: 35.2%, and TT 3.1% among CRC cases and 50.9%, 38.8% and10.3% among controls. Carriers of the TT genotype were less likely to have CRC (OR=0.25; 95%CI: 0.076-0.811;p=0.021) as compared to those with the CC genotype. Genotype analysis of MTHFR A12987C revealed AA:38.9%, AC: 45%, and CC 16% among CRC cases and 37.4%, 50.4% and 12.2% among controls. There wasno significant association between genetic polymorphism at this site and CRC. Haplotype analysis of MTHFRpolymorphism at the two loci showed differential distribution of the TA haplotype (677T-1298A) between casesand controls. The TA haplotype was associated with a decreased risk for colorectal cancer (OR=0.6; 95% CI:0.4-0.9, p=0.03).
Conclusions: The genetic polymorphism of MTHFR at 677 and the TA haplotype may modulatethe risk for CRC development among the Jordanian population. Our findings may reflect an importance of genesinvolved in folate metabolism in cancer risk.