A significantly reduced risk of NHL was associated with the homozygous TT genotype in CBS (rs234706, Ex9+33C>T) (OR = 0.51, 95 % CI 0.31-0.84), the homozygous CC genotype in MBD2 (rs603097, -2176C>T) (OR = 0.37, 95 % CI 0.17-0.79), the heterozygote AG genotype in FTHFD (rs1127717, Ex21+31A>G) (OR = 0.73, 95 % CI 0.55-0.98), and a borderline significantly reduced risk of NHL was observed for the homozygous CC genotype in MTRR (rs161870, Ex5+136T>C) (OR = 0.23, 95 % CI 0.05-1.04).
Meta-analysis for SNPs in the MTHFR, MTR, MTRR and SHMT revealed a reducing effect of the MTR 2756G allele on the risk of NHL (OR=0.902; 95% CI 0.821-0.991, P=0.03).
Single analysis for NHL did not show any significant difference for all the polymorphisms investigated, but in the low-grade NHL subgroup, we found a 2.0-fold risk reduction for the MTRR 66GG homozygous genotype (OR 0.50, 95% CI 0.25-0.99), which was higher (OR 0.37, 95% CI 0.14-0.85) when analyzed in combination with MS 2756AA genotype.