Grant: Doctoral: Vanier Canada Graduate Scholarships

Human breast cancers represent very complex populations of malignant cells and, by the time the disease has begun to spread, this results in very poor outcomes to available treatments. It is thus important to understand the cellular composition of breast tumors, and how this differs from normal breast tissue, so that new therapies to target and abolish the cancer more effectively can be developed. Recent research in our lab has identified a rare subset of "stem" cells in normal human breast tissue. These cells appear able to regenerate a complete normal mammary gland structure when they are placed in a gel that is then transplanted under the kidney capsule in mice that lack an immune system. Interestingly, it appears that human breast cancers are also mixed populations of cells of which only a few can actually propagate the tumour further. If this idea proves to be generally correct, it will be critical to understand what the features of these breast cancer "stem" cells are so they can be effectively killed to prevent any regrowth of the tumour at a later time. The goal of my project is to apply a new method for tracking the growth potential of many single human malignant breast cells transplanted together into mice to test the idea that those able to grow are as rare as believed. This method will also help to establish whether a single breast cancer stem cell has the ability to regenerate a palpable tumor, how to isolate it separate from tumour cells that lack this activity and then analyze the unique molecular features of these malignant breast stem cells. The results will provide understanding of the basic biological properties of human breast cancer stem cells and provide new insights about their abnormal behavior that may lead to the design of new therapies.