ALDH2 and cancer: Several studies have clearly demonstrated that the ALDH2/ADH1B genotypes, which would be expected to result in exposure to high acetaldehyde concentrations, are associated with an increased risk of some types of cancer among drinkers.9–15 Yokoyama et al found that individuals with ALDH2*1/*2 were at high risk for several types of cancer10 and that their risk for oropharyngolaryngeal and esophageal cancers was 11 to 24 times higher than for individuals with ALDH2*1/*1.