Catching lung cancer's 'immune fog' years before tumors form — and clearing it with drugs

UCL researchers discovered that regulatory T cells — the 'brakes' of the immune system — quietly build up as an 'immune fog' months or years before lung cancer appears, letting pre-cancers slip past the body's defenses. Using prototype blood tests, they could spot this fog — and in lab animals, a targeted drug that lifted it halved the share of animals that developed lung tumors and prevented all large tumors. This is 'cancer interception': stopping cancer before it ever becomes cancer. (Human blood and tissue plus animal models; not yet a therapy.)