Although immune checkpoint blockade therapy has revolutionized cancer treatment, a subset of tumors, such as those of the breast, are still largely unresponsive. It is therefore critical that we drastically improve the curative potential of these therapies by understanding the mechanisms by which breast cancer cells mount resistance to immunotherapies. The Epithelial-Mesenchymal Transition (EMT), which converts epithelial cells to quasi-mesenchymal states, endows cancer cells with many traits associated with high grade malignancies. This includes their ability to metastasize to distant organ sites, acquire tumor-initiating abilities, and mount resistance to chemotherapies. In addition to these well-documented features, we have shown that the EMT program also enables breast carcinomas to establish an immunosuppressive tumor microenvironment and drive resistance to immune checkpoint blockade therapy. The Dongre Lab is focused on understanding the mechanisms by which breast cancer cells undergoing an EMT drive  resistance to immunotherapy. Our long-term goal is to interrupt cancer cell-intrinsic immunosuppressive signaling channels, or the EMT program itself,  to potentiate the efficacy of immune checkpoint blockade therapy for poorly responding breast tumors.