Mayo Clinic: Cancer Fight Starts in Thymus, Rewriting the PD-1 Playbook (opens in new tab)

Zhiming Mao spent years studying how the immune system learns to fight cancer, and this week, working in Mayo Clinic's labs, he found the classroom is far earlier in life than medicine ever believed. A Nature Communications study published Thursday shows CD8+ T cells begin acquiring tumor-killing capacity inside the thymus, not after entering circulation, and that PD-1 acts as a brake on that early preparation.