As platelet MAO-B activity is affected by smoking [39], alcohol dependence [35], sex [35], and various medication [31], as well as by liver diseases (cirrhosis, fibrosis, and sclerosis, and hepatocellular carcinoma) [35], in this study, we controlled platelet MAO-B activity, in the large number of subjects (N = 1053), for these possible confounders that were reported to influence platelet MAO-B activity [31,35,38,39,41]. The gene discussed is MAOB; the disease is hepatocellular carcinoma.