MTHFR and lung carcinoma: In this study we genotyped 6 variations in 3 genes related to folate metabolism: rs1801133 and rs1801131 in MTHFR, rs1805087 in MTR, rs1801394, rs1532268 and rs10380 in MTRR. We did not found any significant difference between lung cancer cases and controls in univariable and multivariable analyses in which were considered folate concentration and other SNPs as confounders.