Honjo was honored with the 2018 Nobel Prize in Physiology or Medicine for his discovery of programmed cell death protein 1 (PD-1), a key regulator of the immune response against tumors. He shares the award with Professor James P. Allison, who pioneered research on CTLA-4, another major pathway allowing cancer cells to evade the immune system.

The discoveries of PD-1 and CTLA-4 have paved the way for powerful new cancer therapies that use the body’s own immune system to target tumors. Drugs targeting PD-1 and CTLA-4, called checkpoint inhibitors, are currently being used to treat advanced skin, lung and other cancers. Honjo and Allison were previously recognized for their pioneering role in immunotherapy with the 2014 Tang Prize. (Photo: Kyoto University Institute for Advanced Study)