Tasuku Honjo

Tasuku Honjo is one of the most transformative figures in modern medicine — a physician-scientist whose decades of fundamental research at Kyoto University gave rise to an entirely new class of cancer therapies now used to treat patients worldwide. He is Distinguished Professor at Kyoto University, Director of its Center for Cancer Immunotherapy and Immunobiology, and the 2018 Nobel Laureate in Physiology or Medicine.

Nobel Prize speaker Tasuku Honjo is best known for his discovery of PD-1 (programmed cell death protein 1), a molecule expressed on the surface of immune T cells that acts as a natural brake on immune responses. Identified in 1992 during research aimed at understanding how the immune system distinguishes self from non-self, PD-1 turned out to hold extraordinary clinical significance: cancer cells exploit this pathway to evade immune attack. By blocking PD-1, it became possible to lift that suppression and unleash the body’s own defenses against tumors. This insight seeded a revolution. Anti-PD-1 therapies — including the blockbuster drugs nivolumab and pembrolizumab — are now approved for more than a dozen cancer types, from melanoma and lung cancer to lymphoma and kidney cancer, giving meaningful survival extensions to patients who had exhausted all other options.

Honjo’s scientific contributions extend well beyond PD-1. Earlier in his career he made foundational discoveries in B cell biology, identifying key cytokines including IL-4 and IL-5, and uncovering the mechanism of class switch recombination — the process by which B cells diversify antibody types. His discovery of activation-induced cytidine deaminase (AID), the enzyme that drives both class switching and somatic hypermutation, is considered a landmark in understanding adaptive immunity.

Nobel Prize in Physiology or Medicine

In 2018, Honjo was awarded the Nobel Prize in Physiology or Medicine jointly with James P. Allison of MD Anderson Cancer Center, recognized by the Nobel Committee for establishing an entirely new principle for cancer treatment through inhibition of negative immune regulation. The pair had also jointly received the Tang Prize in Biopharmaceutical Science in 2014. Honjo’s broader recognition includes the Kyoto Prize in Basic Sciences, the Robert Koch Prize, the Warren Alpert Prize, the William B. Coley Award, and the Imperial Prize of the Japan Academy, among many others. He is a member of the National Academy of Sciences (U.S.), the German Academy of Natural Scientists Leopoldina, and the Japan Academy.

His ongoing research at Kyoto University’s Center for Cancer Immunotherapy and Immunobiology continues to explore the frontier of PD-1 biology, including metabolic mechanisms of T cell exhaustion and the next generation of combination immunotherapy strategies.

As a speaker, Tasuku Honjo offers audiences an extraordinary vantage point on one of medicine’s greatest breakthroughs — from the curiosity-driven bench science that uncovered PD-1 to the global clinical reality it created. He speaks with authority and humility about the long arc of scientific discovery, the value of fundamental research, the future of immuno-oncology, and the role of perseverance in translating laboratory insights into life-saving treatments. His talks resonate deeply with senior audiences in healthcare, biopharma, life sciences, and corporate innovation — any organization wrestling with how bold, patient research becomes transformative impact.