ALDH2 and urinary bladder cancer: Our previous case-control study suggested that those with inactive ALDH2 alleles showed increased risk of bladder cancer among drinkers.8 Furthermore, moderate drinkers with flushing response, most of whom were considered to carry inactive ALDH2 alleles, had a higher risk of bladder cancer than those without flushing response in the Japanese cohort study.9 These two epidemiological studies consistently indicate that drinkers with inactive ALDH2 alleles may have an increased risk of bladder cancer.