Besides, genes down‐regulated in the diethylnitrosamine treatment‐induced or E2F1 overexpression‐induced hepatocellular carcinoma models and HNF1A knockout model of type 1 diabetes are also overrepresented, supporting the liver protective roles of metformin.42, 43, 44. The gene discussed is HNF1A; the disease is type 1 diabetes mellitus.