MTHFR and lung carcinoma: However, Siemianowicz et al. [11] in Poland, Hung et al. [9] in Central Europe, and Shen et al. [10] in China showed that individuals with MTHFR TT genotype had an increased risk of lung cancer versus those with the wild-type homozygous variant, while a recent meta-analysis by Mao et al. [20] based on eight case-control study suggested no evidence for a major role of the MTHFR C677T polymorphisms in carcinogenesis of lung cancer.