When the IL-6 promoter methylation level was used to diagnose HCC, its detective value was superior to AFP [area under the receiver operating characteristic curve (AUC) 0.773 vs. 0.686, P=0.027], And the combined use of AFP and IL-6 methylation level can improve the area under the receiver operating characteristic curve (p=0.011). The gene discussed is IL6; the disease is hepatocellular carcinoma.