Biliary tract cancer prognostic and predictive genomics.

Biliary tract cancer (BTC) is comprised of intrahepatic cholangiocarcinoma (ICC), extrahepatic cholangiocarcinoma (EHC) and gallbladder cancer (GBC). These tumors arise in the biliary epithelium, share histological characteristics and are associated with grim prognosis even when diagnosed at early stages. Moreover, its relatively low incidence in developed countries has precluded the development of clinical trials addressing specific differences among BTC subgroups in terms of their biology, treatment response and clinical outcomes. In this scenario, the development of effective treatment strategies for patients has been rather modest. To date, the combination of cisplatin plus gemcitabine remains as the standard first line therapy in advanced disease and after progression to this regimen there are limited treatment options. Next generation sequencing (NGS) studies have assessed the distribution of driver genes and potentially actionable genomic alterations among ICC, EHC and GBC. Here, we outline genomic differences among these subsets and describe key milestones in order to develop novel targeted drugs against BTCs. Although the early results of several studies are promising, international collaboration is critical to conduct adequately-powered trials, enrolling patients from high-incidence countries.