MTHFR and colorectal cancer: Several studies have found statistically significant interactions of variants in the ADH1B [12], ALDH2 [13], CYP2E1 [13, 14], and MTHFR [15–18] genes with alcohol consumption and colorectal cancer, whereas other studies found no interactions with ADH1B [19], ADH1C [19, 20], ADH7 [12], ALDH2 [12, 19, 21, 22], and MTHFR [23–26] variants.