Further analysis found that the serum levels of S100A9 in less-differentiated (Edmondson grade II and III) HCC cases were significantly higher than those in well-differentiated (Edmondson grade I) cases (p = 0.0067), indicating that serum S100A9 might be a potential indicator for less-differentiation in HCC. The gene discussed is S100A9; the disease is hepatocellular carcinoma.