Reply to Brockton's letter

摘要

Although Brockton pointed out that we had cited a work of Ma et al. showing an increased risk of colorectal cancer in those with MTHFR 677TT genotype in our article , he misunderstood our description regarding this issue. We cited the work as a paper revealing an increased risk of colorectal cancer in those with MTHFR 677TT genotype and folate deficiency. Those with MTHFR 677TT genotype and folate adequacy had a decreased risk (odds ratio = 0.32) compared with those with MTHFR 677CC/ CT genotype and folate adequacy (the reference category). Those with MTHFR 677TT genotype and folate deficiency had a modest increased risk (odds ratio = 1.33) compared with the reference category. In short, those with MTHFR 677TT genotype and folate deficiency had an increased risk compared with those with MTHFR 677TT genotype and folate adequacy. Ma et al. described the following sentence in their work, "Low folate levels were associated with higher risk of colorectal cancer for all MTHFR genotypes, but the effect of folate deficiency was especially strong in the Val/Val group."