Plain language summary
This 2012 cross-sectional observational study examines the role of epigenetic gene expression and methylation in 189 patients with colorectal adenocarcinoma, including 128 with MTHFR polymorphisms. The mean age was 61 years and there was a 50/50 gender split. The focus nutrients were folate, vitamins B2, B6, B12, choline, betaine, and methionine, all of which are known to be essential nutrients for DNA synthesis and more specifically have a key role in the 1-carbon cycle, and S-adenosylmethionine (SAM). The study is based on prospective data collection from food frequency and clinical evaluation questionnaires, and blood work. There does not appear to have been any control group or blinding of processes (at least not reported in the study). The results showed that serum folate levels were positively correlated with the equivalent total dietary folate intake and global DNA methylation. No significant differences were found between serum folate levels in relation to the different genotypes of MTHFR polymorphisms such as C677T. A weak association was found between the A1298C polymorphism and lower levels of methylation. No significant findings were reported for the vitamins used in the study. The study concludes that folate intake, serum folate levels, global DNA methylation and age were predictors of clinicopathological staging.
Abstract
Folate, vitamin B2, vitamin B6, vitamin B12, choline, and betaine are nutrients involved in the 1-carbon cycle that can alter the levels of DNA methylation and influence genesis and/or tumor progression. Thus, the objective of this study was to evaluate the association of folate and vitamins involved in the 1-carbon cycle and MTHFR polymorphisms in global DNA methylation in patients with colorectal cancer gene. The study included 189 patients with colorectal adenocarcinoma answering a clinical evaluation questionnaire and the Food Frequency Questionnaire (FFQ) validated for patients with colon and rectal cancer. Blood samples were collected for evaluation of MTHFR gene polymorphisms in global DNA methylation in blood and in tumor. The values for serum folate were positively correlated with the equivalent total dietary folate (total DFE) (rho = 0.51, p = 0.03) and global DNA methylation (rho = 0.20, p = 0.03). Individuals aged over 61 years (p = 0.01) in clinicopathological staging III and IV (p = 0.01) and with + heterozygous mutated homozygous genotypes for the MTHFR A1298C gene had higher levels of global DNA methylation (p = 0.04). The association between dietary intake of folate, serum folate, and tumor stage were predictive of global DNA methylation in patients' blood. The levels of serum folate, the dietary folate and the status of DNA methylation can influence clinicopathological staging.
Methodological quality
Jadad score
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1
Allocation concealment
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No
