The Origins of Cancer Immunology
July 24, 20261 Min Read The Discovery of Immune Checkpoints (A Nobel Story)
July 24, 2026Two people each discovered a brake tumors were using to hide — then the world used this discovery to cure previously untreatable cancers
By the Editors Care Framework & Diagram
Allison finds a molecule that acts as a brake on T cell activation, not an accelerator. In 1996, blocking it in mice doesn’t just shrink tumors — cured mice resist the same cancer again later, proof of lasting immune memory. No drug company wants to fund it at first; ‘immune therapy’ is considered a failed idea. Approved in 2011 as the first-ever checkpoint inhibitor.
Honjo finds a gene in 1992 he expects to trigger cell death — instead, mice missing it develop autoimmune disease as adults. It’s a brake, not an accelerator, in a different location than CTLA-4. A decade later, its partner molecule turns up on tumor cells themselves — tumors that sense they’re under T cell attack actively pull this brake to protect themselves.
CTLA-4 works early, in the lymph nodes, before T cells even head into battle. PD-1 works later, right at the tumor itself, once T cells have already arrived. Blocking both at once hits harder — but with more side effects.
- Allison’s applied, drug-development approach and Honjo’s basic-science curiosity arrived at the same destination from opposite directions.
- Together, they created an entirely new category of cancer treatment — the 2018 Nobel Prize went jointly to both.