This disparity could be attributed to gene–environment interactions, in which ALDH2 (rs671, Glu504Lys) and ADH1B (rs1229984, His47Arg) polymorphisms showed the highest risk of bladder cancer, whereas among never-drinkers, no significant elevation of risk was observed with ALDH2 Glu/Lys compared with Glu/Glu [172]. Here, ALDH2 is linked to urinary bladder carcinoma.