Grant: Doctoral Research Award: Canada Graduate Scholarships

Breast cancer is the most diagnosed cancer across the globe. Though survival rates have been increasing, those who survive face serious negative health impacts, such as the adverse side effects of treatment and large psychological burdens. Approaches to prevent breast cancer could therefore significantly improve population health. Estrogen is a known cause of hormone receptor (HR)-positive breast cancer, the most prevalent form of breast cancer. Recent research has shown that bacteria residing in the gut (the gut microbiome) can influence estrogen levels in the body and suggest that it may contribute to the development of breast cancer. Due to limited clinical studies in humans, this pathway is not understood well enough to take advantage of for therapeutic measures. Our project therefore aims to better explain the role of the gut microbiome by conducting a study of 70 women newly diagnosed with HR-positive breast cancer and comparing them to 70 women without cancer. Questionnaires on lifestyle and diet will inform health factors and stool samples will provide the type and quantity of bacteria present in the gut microbiome. Based on current research, we expect to find women with breast cancer to have higher amounts of estrogen-related bacteria compared to women without cancer. Our deeper sequencing methods will better define these bacterial differences which can then inform possible ways to alter the gut microbiome environment, as it is modifiable by factors such as lifestyle, diet, and probiotic supplementation. This may open the door to a pathway for prevention as well as for improving current treatment methods, as certain microbiome environments have been linked to improved cancer treatment outcomes. Overall, this project will provide an important step forward in approaches for improved cancer therapy and prevention.