Professor Robin Weiss, recognised as one of the most influential scientists in modern virology and cancer biology, passed away on 27 February 2026.
A former Director of The Institute of Cancer Research, London, Professor Weiss made discoveries that reshaped our understanding of retroviruses, HIV and virus associated cancers. His decades of leadership and scientific vision transformed the field and left an enduring legacy that continues to guide researchers today.
Professor Weiss first joined The Institute of Cancer Research (ICR) in 1980, beginning a pivotal chapter in both his career and the institute’s history. He served as Director, which was equivalent to the role of Chief Executive, from 1980 to 1989, and then continued as Director of Research for nine years.
His tenure was marked by bold scientific ambition, a commitment to interdisciplinary progress and an unwavering belief in prioritising research that could deliver tangible benefits for people affected by cancer.
A career full of highlights
Much of Professor Weiss’ most celebrated scientific work took place at the ICR. His research into retroviruses advanced global understanding of how viruses contribute to cancer, and his later pivot into HIV research resulted in discoveries that would prove foundational in the global fight against AIDS.
His most significant achievements included identifying CD4 as the receptor used by HIV to enter human cells, a breakthrough that profoundly shaped subsequent diagnostic, therapeutic and vaccine research. After developing a cell line that served as a common laboratory model for studying virus replication and cell death, he was also the first scientist to demonstrate neutralising antibodies against HIV. Later, his work on a UK HIV isolate named CBL-1 – named after the ICR’s Chester Beatty Laboratories – allowed his colleague Richard Tedder to develop an assay to test for antibodies to HIV, which was subsequently successfully commercialised by the Wellcome Foundation.
In the field of cancer, Professor Weiss helped establish the role that viruses can play in the development of some forms of cancer. Professor Weiss was also part of the team that discovered the NRAS gene, which plays a key part in modulating cell division and is dysregulated in many cancers. NRAS is now considered a key biomarker and is used to guide treatment decisions in various types of cancer, including colorectal cancer and melanoma.
In recognition of his groundbreaking contributions, Professor Weiss received numerous honours throughout his career. These included being elected to the European Molecular Biology Organization (EMBO), becoming a Fellow of the Royal Society and being made an Honorary Fellow of the Royal College of Physicians. His work on retroviruses earned him the M. W. Beijerinck Prize for Virology, and in 2007, he received the prestigious Ernst Chain Prize, awarded by Imperial College London to scientists whose work has substantially advanced the understanding or management of human disease.
Professor Weiss also served as Editor-in-Chief of the British Journal of Cancer for several years. Under his guidance, it evolved into a multidisciplinary journal focused on research that directly benefits patients – a reflection of his deep commitment to ensuring that scientific discovery serves human health.
A wider impact on the research community
Beyond his own laboratory achievements, Professor Weiss was a mentor and advisor to generations of researchers.
Professor Sir Mel Greaves, Founding Director of the Centre for Evolution and Cancer at The Institute of Cancer Research, London, said:
"Robin Weiss was extremely influential in my scientific career. Always ahead of me, we tracked together at UCL as students, then at the Imperial Cancer Research Fund and then finally at the ICR. Robin, as ICR Director, recruited me and was always both inspirational and highly supportive at a personal level.
"I witnessed first-hand how Robin transformed the ICR in the 1980s by introducing cell and molecular biology, setting it on its current path to eminence and success. We all owe Robin a huge debt."
Professor Weiss’ influence extended globally through major collaborations, including research supported by the Gates Foundation, where he helped lead efforts towards HIV vaccine development. His curiosity and dedication also led him to investigate emerging viral threats, such as severe acute respiratory syndrome (SARS) and viruses relevant to xenotransplantation, demonstrating his agility as a scientist.
Professor Jonathan Weber, Professor of Communicable Diseases at Imperial College London and Co-Director of the Research Hub at the Pears Cumbria School of Medicine in Carlisle, worked closely with Professor Weiss for many years. Having looked after people with AIDS as a junior doctor at St Mary’s Hospital, London, Professor Weber was funded by the Wellcome Trust to join the Chester Beatty Labs at the ICR and be trained in retrovirology by Professor Weiss.
Professor Weber said:
"Robin’s laboratory, throughout the late 1980s, was the most stimulating scientific environment at the most extraordinary time. Of the 10 students and postdocs in his lab over the three years I spent there, all went on to professorial university posts in the UK, USA and Europe. His scientific opinion was widely sought and generously given; he encouraged endless scientific visitors, and his lab felt at the very epicentre of the international scientific effort to contain and control the HIV pandemic.
"40 years later, I still reminisce over that extraordinary period under Robin’s wise, forgiving and guiding hand."
A long-lasting legacy at the ICR
Professor Weiss also personally recruited Professor Chris Marshall and Professor Alan Hall to the ICR, both of whom were responsible for molecular oncology publications that laid the scientific basis for significant therapeutic developments decades later.
Professor Kristian Helin, Chief Executive of the ICR, said:
"Professor Weiss oversaw a transformational era for the ICR, strengthening its international reputation and fostering research that pushed the boundaries of what was thought possible. His work laid crucial foundations for new approaches to understanding the links between viruses and cancer, and he championed the development of the institute’s scientific culture – one defined by curiosity, rigour and collaboration."