Although four models have similar performance, we believe that the models with tumor antigens (OPN-CEA-CYFRA21.1 and OPN-CEA-NSE) may be more appropriate than the models with inflammatory proteins (OPN-CEA-CRP and OPN-CEA-SAA) because CRP and SAA are elevated in many diseases including other cancers. The gene discussed is SPP1; the disease is neoplasm.