Dr Karen Vousden, Beatson Institute for Cancer Research, Glasgow, UK, talking at AACR 2009: Looking at the balance between cell senescence and cell death, activating p53 and using senescence to trigger the immune system to attack cancer cells. Cellular senescence is the phenomenon by which normal diploid cells lose the ability to divide, normally after about 50 cell divisions in vitro. Some cells become senescent after fewer replications cycles as a result of DNA double strand breaks, toxins etc