ALDH2 and esophageal squamous cell carcinoma: Following the first study [12], which was conducted in the Japanese population, case control studies in Japan and Taiwan have consistently demonstrated a strong link between the risk of esophageal squamous cell carcinoma (Figure 3) and alcohol consumption in low-activity ALDH2 heterozygotes, with odds ratios (ORs) ranging from 3.7 to 18.1 after adjustment for alcohol consumption.