Regarding the risk of developing HCC, compared to the patients in the low-level group, patients with high ADA levels had an OR value of 1.440 (95% CI, 1.033–2.009; p < 0.05), and the adjusted OR was 0.967 (95% CI, 0.551–1.697; p > 0.05). The gene discussed is ADA; the disease is hepatocellular carcinoma.