Thomas W. Kensler, PhD, a trailblazer in cancer prevention who was among the first to conduct Westernized human clinical trials in China, died July 11, 2025, following an accident while hiking on Mont Blanc in France. He was 76 years old.
Kensler was known for his innovative research on chemoprevention of cancer using compounds found in broccoli and other cruciferous vegetables. He led several clinical trials in the Qidong region of China, including one investigating whether consumption of a broccoli sprout beverage was associated with increased elimination of benzene, an airborne carcinogen common in the area.
Born in Massachusetts in 1948, Kensler received a bachelor’s degree in biology from Hamilton College in Clinton, New York, in 1970, and obtained a doctoral degree in toxicology from the Massachusetts Institute of Technology in 1976.
After postdoctoral work at the University of Wisconsin and the National Cancer Institute (NCI), he joined the faculty of Bloomberg School of Public Health at Johns Hopkins University in 1980, where he rose to the level of professor. In 2010, he became a professor of pharmacology and chemical biology at the University of Pittsburgh School of Medicine and coleader of the Cancer Epidemiology and Prevention Program at the University of Pittsburgh Cancer Institute (UPCI). He later joined the Public Health Sciences Division of the Fred Hutchinson Cancer Center in Seattle, where he worked until he retired in 2024.
A loyal AACR member since 1979, Kensler provided valued service on several scientific and other committees, including as a co-chair of the Annual Meeting Program Committee (2004-2005); a member of the Cancer Prevention Committee (2001-2014) and the Special Conferences Committee (2012-2015); and a member of the steering committee of the 2016 AACR Cancer Progress Report. He also served as a senior editor of the AACR journal Cancer Prevention Research from 2012 to 2017.
He received the AACR-American Cancer Society Award for Research Excellence in Cancer Epidemiology and Prevention in 2007. Other honors include the National Friendship Award from the People’s Republic of China in 2011, the Society of Toxicology Translational Impact Award in 2009, the Oxygen Club of California and Jarrow Formulas Health Science Prize in 2012 (shared with Masayuki Yamamoto), and an NCI Outstanding Investigator Award in 2015.
“Tom Kensler was a cancer research pioneer, especially in the investigation of the mechanisms of induction of cancer by chemicals and the potential for progress in chemoprevention using naturally occurring agents,” said Margaret Foti, PhD, MD (hc), chief executive officer of the AACR. “He was greatly esteemed for his scientific brilliance, his dedication to saving lives through cancer prevention and global cancer research, and his warm and affable personality. Because of his outstanding research in addressing cancer incidence and mortality around the world, we were very proud to recognize his achievements with the AACR-ACS Award for Research Excellence in Cancer Epidemiology and Prevention. He will be dearly missed by all of us in the cancer research community.”
Kensler’s wife, Nancy E. Davidson, MD, FAACR, executive vice president for clinical affairs at the Fred Hutchinson Cancer Center and AACR Past President (2016-2017), said that in honor of Tom’s longstanding contributions as a dedicated AACR member, the family would welcome donations in his memory to the AACR in support of young investigators.
While Kensler’s groundbreaking research expanded the horizons of cancer prevention, his most lasting impact is on the dozens of students and fellows who worked in his laboratory. He was a devoted and effective mentor. Supporting the development of early-career scientists was the professional achievement of which he was most proud, and the achievements of this next generation of cancer scientists are his most enduring legacy.
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Tom was a post-doc when I was a PhD student at McArdle Labs, UW. He was generous and kind to all. While Tom was in Wisconsin, we drove, with Bill Roebuck, from Madison to Alaska. On the way, we hiked the Chilkoot Trail, trekked in the Canadian Rockies and backpacked in Denali National Park. Tom planned the trip and was a great guide. After an AACR meeting in ‘82, Tom, Nancy, Bill and I camped in the Anza-Borrego Desert near San Diego.
Tom's studies in China were so elegant and beautifully designed, from the biochemistry to the epidemiology, thus I was delighted when he lectured to a Cancer Epidemiology class that I taught at the UMN.
Tom and I often took walks, in Wisc., at AACR meetings, and in MN; those usually included ice cream. In the late 1970s, before dry ice was banned as a carry-on item, Tom would buy a gallon of orange custard chocolate chip from the UW Dairy store, freeze it at -70°, pack it in dry ice and take it on his flight to visit family.
I will sorely miss him.
Tom Kensler was an outstanding scientist and mentor and a powerful speaker. I was very sad to hear of his passing through this post. He was a role model to so many junior scientists and influenced so many careers. I hope the memories of good times spent together serve as comfort to his family and friends. With admiration.
Tom Kensler was much more than a PI during my 6 years in the US—he was a friend and a role model, not only for his scientific integrity but also for life. I cherish our moments together in Pittsburgh, Baltimore, and Seattle, including his kindness in welcoming me to his family home during holidays and the many Penguins games we watched live. I am grateful I saw him twice last year in Europe (Greece and Switzerland), sharing once more our talks on science, life, the Ravens, and the Penguins. My thoughts are with his wonderful family—Nancy, Caroline, and Kevin. Tom was a remarkable scientist, a deep thinker, a devoted family man, and a true American. His memory will inspire future generations, and I will do my part to honor his legacy. I will miss him deeply and wish I could thank him once more for launching my independent career and inspiring me in life.
Tom: thank you for being an outstanding researcher, a fabulous mentor (how fortunate I was to have you as my NIH early career award mentor), and a human being of integrity. I wish I had told you that your teaching me for hours about the toxicological mechanism of aflatoxin was not only the first time I truly understood the subject I'd worked on for years, but also helped me understand toxicology much better. Later, when we wrote a paper on how aflatoxin-induced liver cancer in Qidong, China, decreased dramatically after people switched from eating maize to eating rice, you made me laugh describing how you were so proud of one of the figures in that paper that you encased it in plastic, and took it with you on your 3-week kayaking expedition on the Yukon River from Canada into Alaska.
I will miss you, and wish I had the chance to thank you for launching me (and so many others) on a wonderful career.
I am deeply saddened to hear of Tom's passing. I admired Tom's depth and breadth in the scientific continuum of cancer prevention. He made seminal contributions to fundamental research in carcinogenesis and then moved his concepts into the human populations. I considered his work as "tour de force" accomplishments that blazed new trails for me and I believe many others to follow. Tom readily shared his insights to scientific barriers and his solutions with others. He was generous with this time, collegial, fair and honest. His passing is a huge blow to the field. He leaves behind generations of outstanding scientists impacted by his work and mentorship who will continue to move the field forward.
Tom Kensler was a good friend and valued colleague in the field of cancer prevention research for more than 40 years. We had many collaborative interactions but the ones that stand out in my memory are the studies in Qidong, China where he and his colleagues were true pioneers in rigorous clinical trials of broccoli sprouts and its constituents, based on years of basic studies by Tom and his collaborators. His dedication, together with his colleagues, to the proper conduct of a clinical trial and to obtaining meaningful biomarker data are models for all to follow. Tom served on advisory boards at the University of Minnesota and was always focused and thoughtful while maintaining a friendly yet serious and approachable demeanor which was appreciated by all. I was absolutely stunned to hear of his passing; I still cannot believe he is gone. His passing leaves a gaping hole in our cancer prevention research community. He will be sorely missed.
Heartbroken to hear this news.
Tom Kensler was truly a trailblazer in cancer prevention. His remarkable blend of brilliance, accomplishments, generosity, and graceful demeanor made him an outstanding mentor and role model, even to his senior colleagues.
I’ll never forget his advice the last time we met:
“If you're planning to stay in this business for the next 30 years, don’t get discouraged by rejections. Tough skin! Things might not work for a long time, but they’re going to work one time, and that’s all you need.”
He will be deeply missed. 💙
Thomas Kensler's passing marks the loss of a brilliant scientist whose contributions to his field will endure. Beyond his exceptional research and discoveries, he was deeply committed to mentoring and guiding the next generation of scientists. His dedication to his mentees has left an indelible mark on countless careers. He will be remembered not only for his intellectual prowess but also for his kindness, generosity, and unwavering belief in the potential of others.
It is with deep sadness and immense gratitude that I remember my friend and colleague Thomas W. Kensler, whose life and work left a lasting mark on me. Tom and I worked closely for the last 15 years. Tom devoted his career to the cause of cancer prevention with compassion and a deep desire to reduce human suffering. I was constantly inspired by his commitment to science, to cancer prevention, and to public health. The impact of his work will continue long beyond his lifetime. Beyond the achievements, what I will remember most is his generosity, thoughtful insight, and genuine friendship. In every interaction, he brought inspiration, kindness, and a quiet strength. I am honored to have known Tom – as a scientist, a colleague, and most of all, a friend. His absence leaves a space which cannot be filled, but his legacy lives on in the work we do. Tom, you will live in my memory – not just for what you accomplished, but for who you were. Rest in peace, dear friend. You will be missed.
Tom was a dedicated scientific innovator, outstanding educator, and inspiring leader in the field of cancer risk and prevention. I first met Tom as a student in his carcinogenesis and cancer biomarkers course at the Hopkins SPH. He was a generous mentor, an inspiring instructor, and a dedicated and rigorous scientist committed to excellence. His RCT of oltipraz in Qidong, China to reduce aflatoxin-induced liver cancer incidence was one of the best and earliest examples of a well-conceived, molecularly targeted, mechanism- and biomarker-driven, phase II trial in cancer chemoprevention. Tom was also a key thought leader and advocate for our field and served to catalyze AACR’s expanded commitment to cancer prevention in the 90s. Although Tom left us far too soon, he will always be warmly remembered for his many scientific contributions, his leadership, his kindness, and his vision for a world less burdened by cancer because of prevention’s first-order priority.
Tom Kensler was a giant in the field of cancer epidemiology and prevention, leaving a legacy of groundbreaking research, mentorship and friendship. From a personal perspective, I was fortunate to benefit from his guidance and mentorship early in my career, setting the tone for prioritizing cancer epidemiology and prevention as the foundation of my research career and providing a beautiful template for those whom I have mentored. Together with Nancy Davidson, Tom and Nancy set an example for scientific excellence, compassionate care, administrative leadership, and role models for scientists. Tom will be missed.