Molecular Markers of Cholangiocarcinoma

Bile is a fluid that helps us to digest food and its main function is to break down fats in food. Bile is made by the liver and stored in the gall bladder. Bile ducts are tubes that carry bile and they connect the liver and the gall bladder to the duodenum and the small intestine. In people who have had their gall bladders removed, bile flows directly from the liver into the duodenum and the small intestine. The bile ducts and gall bladder are known as the biliary system (Fig. 10.1). Cholangiocarcinoma (CC) is a malignant tumor arising from the bile duct epithelium. They start in mucus glands that line the bile ducts. If cancer starts in the part of the bile ducts within the liver it is known as intra-hepatic. If it starts in bile ducts outside the liver it is known as extra-hepatic. It may arise from the right and left hepatic ducts at or near their junction (hilar cholangiocarcinoma) which are considered as carcinoma of the extrahepatic bile ducts (for a review, please see Refs. [1–8]). Cancers of the biliary system are almost always adenocarcinomas. The incidence of cholangiocarcinoma reveals wide geographic variations: the highest incidence is reported in areas suffering from endemic infestation with liver fluke. The liver flukes, Opisthorchis viverrini and Clonorchis sinensis, which induce cholangiocarcinomas, are common in Africa and Asia, especially in Thailand and Laos in Southeast Asia, and in some parts of China. Intrahepatic cholangiocarcinoma is the second most prevalent intrahepatic primary cancer. Hilar cholangiocarcinoma is the fourth most common gastrointestinal malignancy.