John G. Gribben

John G. Gribben is a senior figure in the hematology and lymphoma research community, widely recognized for his seminal contributions to understanding CLL immunobiology and his clinical leadership in defining BTK inhibitor therapy. As Professor of Experimental Cancer Medicine at Barts Cancer Institute, Queen Mary University of London, he has pursued an interdisciplinary research program bridging lymphocyte signaling, the tumor microenvironment, and clinical outcomes over more than three decades—first at Dana-Farber Cancer Institute and Harvard Medical School, and subsequently in London. Gribben's laboratory work in the 1990s and 2000s established the importance of T-cell dysfunction and co-stimulatory pathway defects in the CLL tumor microenvironment, identifying mechanisms by which CLL cells evade immune surveillance. He characterized the role of CD28/B7 signaling, PD-1/PD-L1 interactions, and regulatory T cells in CLL progression, providing foundational context for the eventual development of immunotherapy approaches in CLL. His translational studies established MRD negativity as a clinically meaningful endpoint in CLL trials, influencing how modern trials are designed and analyzed. In the era of targeted therapy, Gribben has been an active contributor to the clinical evaluation of BTK inhibitors—including ibrutinib, acalabrutinib, and zanubrutinib—and BCL-2 inhibitor venetoclax in CLL, including in the context of patients with del(17p)/TP53-mutated high-risk disease. He is a member of the iwCLL (International Workshop on CLL) guidelines committee and has contributed to the updated 2018 criteria for CLL diagnosis and response assessment. His broad expertise in lymphoid malignancies, combined with his laboratory platform, has made him one of the United Kingdom's most impactful hematology researchers.