Meta- and Pooled Analyses of the Methylenetetrahydrofolate Reductase (MTHFR) C677T Polymorphism and Colorectal Cancer: A HuGE-GSEC Review

摘要

Worldwide, over 1 million cases of colorectal cancer (CRC) were reported in 2002, with a 50% mortality rate,nmaking CRC the second most common cancer in adults. Certain racial/ethnic populations continue to experiencena disproportionate burden of CRC. A common polymorphism in the 5,10-methylenetetrahydrofolate reductasen(MTHFR) gene has been associated with a lower risk of CRC. The authors performed both a meta-analysis (29nstudies; 11,936 cases, 18,714 controls) and a pooled analysis (14 studies; 5,068 cases, 7,876 controls) of thenC677T MTHFR polymorphism and CRC, with stratification by racial/ethnic population and behavioral risk factors.nThere were few studies on different racial/ethnic populations. The overall meta-analysis odds ratio for CRC fornpersons with the TT genotype was 0.83 (95% confidence interval (CI): 0.77, 0.90). An inverse association wasnobserved in whites (odds ratio ¼ 0.83, 95% CI: 0.74, 0.94) and Asians (odds ratio ¼ 0.80, 95% CI: 0.67, 0.96) butnnot in Latinos or blacks. Similar results were observed for Asians, Latinos, and blacks in the pooled analysis. Theninverse association between the MTHFR 677TT polymorphism and CRC was not significantly modified by smokingnstatus or body mass index; however, it was present in regular alcohol users only. The MTHFR 677TT polymor-nphism seems to be associated with a reduced risk of CRC, but this may not hold true for all populations.