For something so small, the thymus has had an oddly quiet life in medicine. It sits behind the sternum and helps train T cells, the immune system’s frontline recognizers. In childhood, that job is essential. Later, as the thymus shrinks and gives way to fatty tissue, it has often been treated as yesterday’s organ, useful early on, then mostly spent. Two new studies suggest that view may have missed something important. Researchers at Mass General Brigham report that adults with healthier-looking thymuses on CT scans were more likely to live longer and less likely to die from heart disease or develop lung cancer. In a separate study, cancer patients with better thymic health also tended to do better on immunotherapy, one of modern oncology’s most important treatments. Both papers were published in Nature, and together they make a case that the adult thymus may still be doing more work than many doctors assumed. Overview of real-world cohorts and study design. (CREDIT: Nature) “The thymus has been overlooked for decades and may be a missing piece …