For instance, a mutation in the epidermal growth factor receptor (EGFR) affects the therapeutic response to, and outcome of, tracheal, bronchus, and lung cancer, and presence of this mutation varies from 9·1% in the Dutch population to 51·4% in east Asia.52, 53 As another example, the *2 allele of mitochondrial aldehyde dehydrogenase (ALDH2*2), which is associated with decreased metabolism of alcohol, higher alcohol toxicity, and possible carcinogenicity, is more prevalent in east Asian populations than in other populations.54 This evidence concerns the gene ALDH2 and lung carcinoma.