Methylenetetrahydrofolate reductase polymorphisms and colorectal cancer prognosis: A meta-analysis

Background The present study focused on understanding the prognostic value of the methylenetetrahydrofolate reductase (MTHFR) single nucleotide polymorphisms rs1801133 (C667T) and rs1801131 (A1298C) in patients with colorectal cancer (CRC). Methods A systematic literature search was conducted in March 2016. Databases, including Medline, EMBASE, Cochrane and Chinese databases (including CNKI, Wanfang and VIP), were searched to identify the relevant articles describing MTHFR polymorphisms in patients with CRC. Data regarding overall survival (OS), progression-free survival (PFS) and disease-free survival (DFS) were collected and analysed. Results Twenty-four studies with 5423 patients with CRC were included. Significant differences in OS, PFS and DFS were not observed among the different comparisons of patients carrying different alleles of the MTHFR rs1801133 polymorphism (including TT versus CC, TT versus CT + CC, CT + TT versus CC and CT versus CC). Compared with patients with the rs1801131 CA + AA genotypes, patients with the CC genotype had a shorter OS (hazard ratio = 1.85; 95% confidence interval = 1.30-2.65) and DFS (hazard ratio = 2.16; 95% confidence interval= 1.19-3.93). Significant differences in OS, PFS and DFS were not observed among the other patient groups (including CC versus AA, CC + CA versus AA and CA versus AA). Subgroup analysis of rs1801133 and rs1801131 showed that patients with CRC from Asian regions and Western regions demonstrated similar results. Conclusions The MTHFR rs1801133 polymorphism was not associated with the prognosis of patients with CRC; however, rs1801131 may be associated with the prognosis of patients with CRC. Well-designed prospective studies are necessary to obtain a better understanding of the prognostic value of rs1801133 and rs1801131.