Eq 1 also showed a high AUC (>0.784) in the same comparison between IDACP and other malignancies, and, in addition, Eq 1 gave a high AUC (>0.8) for healthy controls versus cholangiocarcinoma, healthy controls versus hepatocellular carcinoma, and IDACP versus duodenal cancer. Therefore, Eq 1 appears to effectively combine the marker abilities of IGFBP2, 3 and CA19-9. The gene discussed is IGFBP2; the disease is cholangiocarcinoma.