Two different types of cancer can develop in the liver. The more common malignancy is hepatocellular carcinoma, which arises from hepatocytes. Less common is hepatic cholangiocarcinoma (bile duct cancer), which arises from bile duct cells or undifferentiated hepatocytes. Both cancers are difficult to treat, and the number of newly diagnosed cases has increased in recent years. In the United States, they are the second leading cause of cancer deaths today and are the fastest growing type of cancer in terms of new cases. Mathias Heikenw?lder of the German Cancer Research Center (DeutschesKrebsforschungszentrum, DKFZ) said, “So far, we have few clues about what promotes bile duct cancer, so we have no possibility to use drugs to stop the process. ” “In our current work, we have not only identified the key signaling pathways that cause the transformation of bile duct cells into cancer, but we have also shown several possibilities to interrupt this cancer-promoting process.” Further major contributors to the current study are colleagues Dirk Haller of Heikenw?lder from the Technical University of Munich (TUM), as well as researchers from the German Research Center for Environmental Health (Helmholtz-Zentrum München), the University Hospital Tübingen and the University of Tübingen. The scientists first studied liver tissue samples from mice and humans. In the bile duct cancer environment, they always found very high levels of harmful reactive oxygen species (ROS). The researchers will conduct preclinical studies to check whether these substances may be used to affect established bile duct cancers and which genetic factors may play a role in this process.