Molecular genetics and targeted therapeutics in biliary tract carcinoma

Abstract

The primary malignancies of the biliary tract, cholangiocarcinoma and gallbladder cancer, often present at an advanced stage and are marginally sensitive to radiation and chemotherapy. Accumulating evidence indicates that molecularly targeted agents may provide new hope for improving treatment response in biliary tract carcinoma (BTC). In this article, we provide a critical review of the pathogenesis and genetic abnormalities of biliary tract neoplasms, in addition to discussing the current and emerging targeted therapeutics in BTC. Genetic studies of biliary tumors have identified the growth factors and receptors as well as their downstream signaling pathways that control the growth and survival of biliary epithelia. Target-specific monoclonal antibodies and small molecules inhibitors directed against the signaling pathways that drive BTC growth and invasion have been developed. Numerous clinical trials designed to test these agents as either monotherapy or in combination with conventional chemotherapy have been completed or are currently underway. Research focusing on understanding the molecular basis of biliary tumorigenesis will continue to identify for targeted therapy the key mutations that drive growth and invasion of biliary neoplasms. Additional strategies that have emerged for treating this malignant disease include targeting the epigenetic alterations of BTC and immunotherapy. By integrating targeted therapy with molecular profiles of biliary tumor, we hope to provide precision treatment for patients with malignant diseases of the biliary tract.

Keywords: Biliary tract carcinoma; Cholangiocarcinoma; Gallbladder carcinoma; Molecular genetics; Personalized treatment; Precision therapy; Targeted therapy.

Figure 1

Molecular and genetic changes that occur during pathogenesis of malignant neoplasms in the biliary tract. BilIN: Biliary intraepithelial neoplasm; CIS: Carcinoma in situ; COX2: Cyclooxygenase 2; FHT: Fragile histidine triad; GB: Gall bladder; HER2: Human epidermal growth factor receptor 2; iNOS: Inducible nitric oxide synthase; IPNB: Intraepithelial papillary neoplasm of the bile duct; LOH: Loss of heterozygosity; MUC5AC: Mucin core protein 5AC.

Figure 2

Targeted agents and their sites of action in biliary tract carcinoma.