Relation of red blood cell's folate and methylenetetrahedrofolate reductase C677T polymorphism to colorectal adenoma

Red Blood Cell's (RBC)’s folate may be related to decreased risk of colorectal adenoma. Methylenetetrahydrofolate reductase (MTHFR) is a key regulatory enzyme in folate metabolism. The MTHFR C677T polymorphism is located in the Exon 4 region and is associated with the change of folate level. This study evaluated the associations between RBC’s Folate levels and colorectal adenoma risk, taking into account whether this associations is modified by MTHFR Polymorphism. In a case-control study conducted from January to October 2007 in Endoscopy-Colonoscopy ward of Shahid Faghihi Hospital, Shiraz. Participants were 177 case of colorectal adenoma who had pathologic-confirmed adenomatous polyps in full colonoscopy examination and 366 controls without polyps in full colonoscopy. Fasting venous blood were drawn from patients in order to determine RBC’s folate and to identify the MTHFR polymorphism by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. Gender Distribution in the patient group were 57.6% male and 42.3% female and control group consisted of 55.1% male and 43.9% female. 50.2% of cases and 49.2% of controls were in the age group “45 years and above”. The T allele frequency was 56.6% in control group and 34.4% in colorectal adenoma patients. There was a significant association between T allele in -677 position of MTHFR gene and colorectal adenoma susceptibility (OR: 1.85, 95% CI: 0.76-4.24, P<0.001). Mean concentration of RBC’s folate was not statistically significant among three groups with TT genotype (mutation homozygote), CT genotype (heterozygote), and CC genotype (wild-type homozygote) (P>0.05) but mean concentration of RBC’s folate was the lowest in TT genotype compare with two other genotype. Odd's Ratio for low (<140ng/ml) versus high level of RBC’s folate in participants with TT genotype was (OR: 2.08, 95% CI: 0.10-2.19, P<0.05) as compare with the CC ones. The result of this study suggested an inverse association between RBC's folate concentration and colorectal adenomas risk, which may be more relevant for those with the MTHFR TT genotype.