[Brooks and Zakhari 2014]. Genetic studies (candidate gene studies, meta-analyses, and GWAS) of alcohol-associated cancers (AAC; e.g., upper aerodigestive tract cancers, hepatocellular carcinoma, breast cancer, colon cancer, and thyroid cancer) have repeatedly implicated risk alleles in alcohol metabolism genes, including ADH1B, ALDH2, and other ADH genes, especially in Asian populations [Hidaka and others 2015; Liu and others 2016; McKay and others 2011; Wang and others 2014a; Wang and others 2014b; Wu and others 2012; Zhang and others 2015]. Furthermore, ADH1B and ALDH2 alleles showed interaction with alcohol use behaviors in determining AAC risk [Masaoka and others 2016; Maurya and others 2014; Siegert and others 2013; Zhang and others 2014b]. Beyond alcohol consumption, ADH and ALDH alleles seem to interact with other factors in relation to cancer risk, such oral hygiene [Tsai and others 2014]. The effects of ADH1B and ALDH2 do not appear to be limited to cancer onset risk, but also contribute to the cancer prognosis [Kagemoto and others 2016; Tucker and others 2014]. To understand better the mechanisms that link ADH1B and ALDH2 with the predisposition to cancer, different authors have investigated the genomic features of AAC tissue. Both the ADH1B and ALDH2 genes showed downregulation in different
