What Does the Thymus Have to Do With Cancer?

Siddhartha Mukherjee says a talk from someone at Harvard used AI to read CAT scans and found one correlate of disease: whether the thymus was still there. People with an intact thymus tended to have less autoimmune disease and less cancer. People who lost the thymus with age tended to have more.

He says the study is correlative, not causal, and that someone could propose 10,000 ways to probe it. The thymus is why T cells are called T cells. He describes it as the nursery, or the kindergarten, where T cells grow up, and he says it naturally involutes and dies. He compares the possible marker to Lipitor or to hypertension in heart disease: the size of the thymus, or whether it is still present. The test he wants starts in animals, by putting a new thymus into an older animal whose thymus is gone.