The lethal impacts of cancer are not confined to local effects of the growing tumor; they also involve extensive interactions with host tissues. Such interactions, which can either combat disease progression or promote it, are poorly studied compared to tumor growth but have major impacts on morbidity and mortality in patients. Notably, the complex mechanisms underlying host-driven aspects of malignancy can benefit from analysis in simple systems. In this study, David Bilder will use the fruit fly model Drosophila melanogaster to investigate how host tissues respond to the presence of tumors. Their goal is to identify new aspects of the interactions between host tissues and tumors, which can have major impacts on the progression of cancer. The researchers will use a reductionist cancer model in the flies, which shows many host responses to tumors that are similar to those seen in humans, such as cachexia and an immune response. They will investigate how fly tumors evade the immune system, and identify host proteins that are secreted into circulation in response to the presence of a tumor. By studying these interactions in the simple fly system, the researchers hope to identify unappreciated aspects of tumor defense that could be relevant to human cancer.