Cancer is the leading cause of premature death in Canada, and the number of new cases continues to rise as the population grows and ages. Based on current rates, 38 per cent of Canadian women and 44 per cent of Canadian men will develop cancer in their lifetimes, many when they are 70 or older. Traditionally, physicians assess the severity of cancer tumours by removing tissue samples from a patient and assigning a severity score based on what they see under the microscope. This process can be time-consuming and yields limited information. Recent discoveries have identified a number of molecules produced by cancer cells. Gerald Li is working on an optical imaging system to detect and evaluate the presence of these molecules. In particular, his focus will be on the use of specially designed probes that will flag these molecules, allowing a physician to immediately identify malignant cells. This system will make it possible to image various parts of the body to detect cancer earlier, predict which pre-cancerous lesions will become tumours, and image tumours in the operating room to help determine the boundary between healthy and malignant cells. It will also assist in the selection of treatments targeting cells that create these molecules.