Grant: Regional Partnership Program Fellowship

Breast cancer is the most common cancer affecting Canadian women and accounts for nearly 30% of all newly diagnosed cancer cases. Despite a large number of new treatment choices including immune-based therapies, it is still difficult to predict the outcome of breast cancer and the response to treatment. A major goal of my research is to investigate how the presence or absence of estrogen receptors on breast cancer cells changes the expression of the immune markers, called HLA-II. This is important because the immune system needs to see tumor proteins (called antigens) on breast cancer cells in the same way as it sees bacteria or viruses. Otherwise the immune system treats the tumors like self and ignores them, or worse still, it suppresses any attempt to eliminate them. Our previous studies suggest that tumor cells which carry a certain HLA-II marker tag the tumor for immune recognition. This HLA-II marker was expressed differently in estrogen receptor positive and negative breast cancers. This suggests that the estrogen receptor molecular pathway influences the immune response to breast cancer cells. My proposed research will test whether blocking the estrogen receptor and other molecular pathways will alter the HLA-II markers on tumor cells and their recognition by the immune system. It is anticipated that this study will improve our understanding of how a tumor cell can be altered to stimulate an effective immune response and consequently, aid in developing new approaches to cancer treatment.