In Central Chinese populations, the heritability of esophageal cancer is estimated at around 49% (Han et al., 1994; Li et al., 1998). East Asian migrants in America also have a much higher esophageal cancer incidence than European Americans and African Americans (Parkin et al., 1997), indicating the pronounced heritability of esophageal cancer. Therefore, the incidence of esophageal cancer is affected by multiple factors that interact with the ALDH2*504Lys allele frequency in a complex way. That complexity could explain the differences between the distributions of esophageal cancer and the ALDH2*504Lys allele carriers in East Asia.
