Aging brings two opposing trends in cancer risk: first, the risk climbs in our 60s and 70s, as decades of genetic mutations build up in our bodies. But then, past the age of around 80, the risk drops again – and a new study may explain a key reason why. The international team of scientists behind the study analyzed lung cancer in mice, tracking the behavior of alveolar type 2 (AT2) stem cells. These cells are crucial for lung regeneration, and are also where many lung cancers get started. What...