Value of serum and bile levels of IGF-1 in discriminating cholangiocarcinoma from other causes of extrahepatic biliary obstruction

Cholangiocarcinoma (CCA) is a highly fatal malignant tumor with increasing incidence rates worldwide. Many biomarkers were suggested for diagnosis of CCA. Insulin-like growth factor 1 (IGF-1) stimulates mitosis, inhibits apoptosis and plays an important role in molecular pathogenesis of CCA. The aim of this study was to evaluate the performance of IGF-1 level in serum and bile as a diagnostic marker for extrahepatic CCA. The study was conducted on 127 patients with extrahepatic obstructive jaundice diagnosed as extrahepatic CCA (group 1, 45 cases), other malignant causes of extrahepatic obstructive jaundice (group 2, 37 cases) and benign causes of extrahepatic biliary obstruction (group 3, 45 cases). Level of IGF-1 was measured for all patients in collected serum samples as well as in bile samples collected during endoscopic retrograde cholangio-pancreatography (ERCP) or through percutaneous transhepatic cholangio-drainage (PTCD). Results: Bile level of IGF-1 was significantly elevated in extrahepatic CCA patients in comparison to other groups (P<0.001). On the other hand, no significant difference in serum level of IGF-1 was noticed among different groups. Conclusion: Measurement of IGF-1 level in bile (but not in serum) can distinguish CCA from other causes of extrahepatic biliary obstruction.