All cells are programmed to die eventually. If cells don't die normally, they can become harmful. For example, cancer can result when cells that should die keep growing instead. Each cell produces 10 to 15,000 proteins, with approximately 25 to 50 per cent of these involved in transmitting signals from the outside to the inside of the cell. My research is investigating how signals are sent within individual cells during the process of cell death. Signalling proteins bind to receptors on the cell surface to regulate growth and determine whether a cell lives or dies. The function of many signal proteins is to keep cells from undergoing apoptosis (cell suicide). My research team has deciphered the function of some key proteins and is continuing to study how proteins determine whether cells live or die. Our goal is to find ways to stimulate or block cell growth or death, which could lead, for example, to the ability to force cancer cells to die. We are also examining macrophages, scavenger cells that clean up debris and are important in the development of atherosclerosis (narrowing of the arteries), and the function of inflammatory cells in the immune system that respond to infection. This research will increase understanding of cell death and may lead to the development of new drug therapies for cancer, cardiovascular disease or inflammatory conditions such as asthma.