Dr. Michael Paul Cancro

On September 10, 2026, the University of Pennsylvania hosted the “Michael P. Cancro Symposium”. Leading scientists presented groundbreaking work, and former trainees and colleagues presented thoughtful and heartfelt remembrances.

I was Mike’s PhD thesis student from 1995 – 1999. Even before we met, I had heard stories.

Mike and I both grew up in Silver Spring, MD. We both studied zoology at the University of Maryland, College Park. We both had fond memories of Bill Higgins, a charismatic professor. We both studied plasmacytomagenesis at the NIH, in the laboratory of Mike Potter - Mike as a PhD student, me as an undergraduate.

Mike had left an indelible impression. On Mike Potter and Bill Higgins, on Betty Muchinski, a scientist in the lab and her husband, Fred, an investigator down the hall, and on others.

I eventually met Mike in person January 1990, interviewing as an MD/PhD candidate. I was taken by the photograph on his desk, of him holding a small baby Robin, face to face, eyes locked, him with big eyes and a wide smile.

During the interview, I referred to “memory B cells”. “What exactly is a memory B cell?”, Mike asked. Naively, I sketched a simple diagram of B cell development and activation, labeling one circle “MBC”.

Now, Mike had devoted considerable thought to the concept of memory. He had chopped tens of thousands of fragments of spleens, analyzing the influenza response with Norm Kleinman. He seized upon the opportunity to teach in his skilled, Mike-like way. “Really?! How can you distinguish a MBC from another B cell? What can it do differently? Are you sure there are “MBCs”? Could memory be increased antibody titers? Increased frequencies of antigen-specific B cells?”

He planted a seed.

A few years later, I joined Mike’s lab as a PhD student. Dave Allman had finished not too long before, publishing his seminal papers, “Peripheral B cell Maturation I and II”. The core lab was Mike, Vicky Lentz, Ada Gomelsky, and an array of post-bac students.
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Mike was focused on understanding B cell development at the marrow / periphery interface, the stage now termed “transitional B cells.” Vicky was studying A/WySn/J mice, a strain with a single locus defect – encoding what turned out to be BlyS/BAFF-receptor - that blocked full maturation into the mature B cell pool. This work ended up being quite significant. It led to the elucidation of critical roles of the BlyS (aka BAFF) family in B cell survival.

In 2011 a monoclonal antibody blocking BAFF/BAFF-R interactions, Benlysta, would become the first the new drug licensed for the treatment of systemic lupus erythematosus since hydroxychloroquine in the 1950s. I think of Vicky and Mike fondly and with pride each year when I give my B cell and Antibody Directed Pharmacology lecture to Yale medical students.

My thesis work took another tact to the larger question of regulation of peripheral immature B cell survival. I asked about the potential role of Bcl-2 family members. After determining that established members were expressed similarly between immature and mature peripheral B cells, I devised a degenerate PCR primer approach to look for novel Bcl-2-related mRNAs. I identified a little-known member, A1, and demonstrated that its upregulation was tightly correlated with immature peripheral B cell development.

I reread my thesis this week and was struck by the experimental rigor and the clarity of expression. These are hallmarks of training with Mike, and I am grateful.

Several years later, at Yale, I was privileged to postdoc with Mark Shlomchik, who credits Mike for his decision to pursue a PhD in immunology. Mark had developed a system that generated large numbers of antigen-specific B cells. This system offered the potential to directly compare memory B cells with their naïve precursors. Here was the opportunity to directly address Mike’s memory B cell questions. Yes, memory B cells are distinct from naïve B cells. They have distinct markers. There are subsets that differ in phenotype and function. They are generated at different times in the immune response and have different proliferative histories. Further, with Jean Sholtz and Mike, we demonstrated that memory B cell subsets differ in their dependence on BlyS for survival.

Mike’s loss was devastating. I had expected we would continue to talk. My family always looked forward to stopping by on our way to and from Connecticut and Maryland. We miss him.

I will recall fondly always the time I spent in Mike’s lab for my PhD. I will remember the scientific musing with Mike, Avinash Bhandoola, and Denise Gay over smoking and coffee at the Bio Pond. I will remember Mike giving up smoking but not giving up mouth pipetting. I will be forever indebted to Mike for modeling intellectual curiosity, scientific integrity, and rigor.

I knew Mike for about twelve years, from when I came to Penn in 1999 until I left in 2011. I wasn't a B-cell person, and although Mike and I collaborated a little scientifically, most of my interactions with him were through the Immunology Graduate Group—IGG—and simply as a fellow member of the Penn immunology community.

Mike had already been at Penn for more than twenty years when I arrived, and he had an extraordinary institutional memory. When I took over as chair of IGG, around 2003, Mike was a kind of de facto elder statesman on the executive committee. If you wanted to know why we did something a particular way—or why perhaps we shouldn't do it some new way without thinking carefully about it—Mike generally knew.

But what I came to appreciate was that this wasn't simply institutional memory for its own sake. Mike cared enormously about the rigor and depth of scientific training. He had very definite ideas about what it meant to educate a young scientist well, and he wasn't shy about expressing them.

One story Mike used to tell captures that wonderfully. When Mark Shlomchik came to Penn for his MD–PhD training, Mark apparently talked with Mike about working in his laboratory. Mike told him, “You're too smart to work for me. You should go work for Martin Weigert.”

It was classic Mike—funny and self-deprecating. But underneath the joke was something quite serious. His first concern wasn't acquiring a talented trainee for himself. It was figuring out where that trainee would receive the education that was right for him.

Mike loved data and he demanded rigor, but he also just loved ideas. One of my favorite memories of Penn is walking into the Au Bon Pain in the lobby of our research building in the morning and finding Mike there with Avinash Bhandoola, Dave Allman, and whoever else had gathered that day—despite the fact that some of their labs weren't particularly close by. There would be coffee cups on the table and some scientific, theoretical, or philosophical discussion underway. And if you stopped, you were welcome to join in.

And when I remember those conversations, I remember Mike smiling. Mike smiled a lot. Sometimes it was simply this wonderfully warm smile. And sometimes it was that slightly mischievous, Cheshire-cat smile that suggested he was enjoying where the conversation was going—or perhaps where he was about to take it.

I've thought about why Mike remains such a strong part of my memory of Penn. There were many extraordinary scientists who defined Penn Immunology during those years. But Mike was different. Mike was a constant. For me, in some ways, he came to embody Penn Immunology itself.

He knew its history. He cared about its standards. He cared about its trainees. He loved data, but he also loved ideas. And he loved the community in which those ideas could be argued about, laughed about, and shared.

Institutions are programs and departments and buildings, but ultimately their character comes from people. Mike was one of those people who gave Penn Immunology its character.

And when I picture that Penn Immunology now, I picture Mike—probably with a cup of coffee, engaged in an argument about some interesting idea, and almost certainly smiling.

Dr. John Wherry recently announced that Warren Pear, MD, PhD, Gaylord P. and Mary Louise Harnwell Professor, has been awarded the inaugural Michael Cancro Distinguished Faculty Mentoring Award.

Warren has been recognized for his exceptional commitment to mentoring colleagues, fostering professional development, and creating an inclusive academic environment. This prestigious award celebrates faculty who go beyond their formal responsibilities to guide others toward professional success.

This inaugural award honors our beloved colleague Michael Cancro, who passed away in February 2025. Over his 49 years at Penn, Dr. Cancro made an indelible impact, particularly through his dedication to mentoring colleagues. The nomination committee felt that Warren's outstanding commitment to mentoring faculty perfectly embodies the spirit of this award and honors Mike’s legacy.

I recently learned of Dr. Cancro’s passing and immediately felt the immense loss of a brilliant mentor, scientist, and friend. Like many others, I first met Dr. Cancro during my immunology course at Penn in the spring of 2012. Enthralled with both the subject and Dr. Cancro’s teaching, I nervously approached him at the end of the semester to ask if I could rotate in his lab that summer. I had no prior lab experience but was planning to apply to medical school the following year. He kindly offered a time to come by the lab to discuss the possibility further.

At the designated time as to not be late, I walked to the John Morgan Building and made my way up the stairs to the lab at the end of the hall on the second floor. I was immediately struck by the trashcan sitting outside the door—something I would later come to recognize as a tribute to his cleanliness. I had never been to a research lab before and wasn’t entirely sure what to do, so I knocked. One of the graduate students or post-docs at the time—Martin, Vishal, Radhika, or Mike O.—opened the door and showed me to the corner office. Dr. Cancro’s head popped out of the door, as it often would, and he said in his distinct cadence, “Ah, Sam, come sit.”

Two things about that conversation have always stuck with me. First, he almost immediately asked if I was a good baker, noting—as a connoisseur of both—that “science is like baking, precise and exact.” I of course said yes, though internally, I was panicking. In truth, I was (and still am) a terrible baker. I hate following recipes and much prefer to season to taste rather than measure—an approach completely antithetical to good science. Second, I distinctly remember him stating that the rotation would be on a trial basis. I could never quite tell if that was due to my inexperience or my unconvincing white lie.

Suffice it to say, I spent that summer and the rest of my senior year learning every aspect of immunology I could from Dr. Cancro and his team. Slowly, the alphabet soup of immunology began to make sense. As so many of his former students have said, one step into the Cancro Lab and you'll be hooked on science forever. It is entirely thanks to Dr. Cancro that I ever pursued an MD/PhD program.

Though my career path eventually took me away from Penn, I would reach out to him now and then—for honest feedback on a grant proposal or simply to catch up at an immunology meeting. One year at AAI, I fondly remember chatting over a tray of tamales in Austin, Texas. It was always such a joy to listen to the stories of a true renaissance man.

The last time I saw Dr. Cancro was in November 2023. I was flying to Philadelphia for a conference and reached out to see if he might be in town. He welcomed me back to his corner lab with open arms. The three of us—Jean included—sat down to catch up and, of course, to chat about my most recent scientific endeavor. I had come to campus to see him, but in typical Dr. Cancro fashion, I left with an invitation to write a review for JLB. He was always looking for ways to support the science and careers of his mentees—a true professor of learning through and through.

Dr. Cancro laid the foundation for my career, as he did for countless others, through his guidance and mentorship. He was my scientific guiding light, a north star if you will; if Dr. Cancro believed it was good science, then I believed it too. Though we were often at a distance, his presence in my life will be deeply missed—and my memories of him will be fondly cherished. To his beloved family, I am so sorry for your loss.

I had the privilege of taking Immunobiology with Mike in the spring of 2023, which sparked my deep passion for immunology. The class was challenging, as immunology is no easy subject, but Mike's excitement and passion were contagious. After taking the course and becoming engrossed in the subject, I decided to apply to immunology graduate programs and grants. I reached out to Mike for advice, and at our first meeting, we connected over our shared experience of growing up in the Maryland area and pies from the Barbara Fritchie Restaurant. He encouraged me to pursue immunology and mentored my grant application on B cells. When that plan did not work out, he recommended the NIH postbac program, connecting me with his contacts there. When I was accepted to a lab, he shared my excitement. We remained in contact throughout my fellowship, and he continued to support my preparations for applying to PhD programs this coming fall. Mike will be profoundly missed. I send my deepest condolences to his family and friends.

Mike wandered into my laboratory at Maryland in 1973-74 looking for some lab work. I had just arrived and was busy setting up a lab and teaching. He soon connected me with Mike Potter, and the NIH - UMD Zoology/Biology connection was established. Mike Potter was his adviser while I served as his co-adviser and connection to Maryland. Several Maryland graduate students (too many to mention!) followed Mike to the NIH to complete Ph.D. degrees in B cell immunology with Mike Potter or one of his colleagues. Mike was a true pioneer; his experiences and initiative established the means for many others to be successful. I also remember Mike as a great musician (guitar in those days) and advocate for social justice and related causes. RIP, Mike!!!

Mike is the reason I've been in immunology since taking the (too short!) Immunology course with him as a Penn Med student in the late 1980's. He planted the seeds that led to my changing my focus for my PhD from Neuroscience to Immunology, and I've been happily contributing to this field ever since, and trying to pass on just a bit of the excitement about immunology that Mike sparked in so many of us during his long career as one of the great teachers at Penn and in Immunology. During my Ph.D. training down the hall from his lab in the John Morgan Building , I had many stimulating conversations at the endlessly percolating coffee machine on the floor, and It was a pleasure to run into Mike at meetings from time to time. Happy circumstances led me to publish a paper with Mike a few years ago on Tbet+ B cells in SLE.that I'll now cherish even more. I and I’m sure many others in the Immunology and Penn communities will miss him terribly.

I was his Admin in my second job at Penn. One of the best Professors I have ever worked for. Funny, caring but didn't suffer fools gladly so we got on like a house on fire. He told me one time that he I reminded him of one of his exes from Hamilton Ontario which I could only take as a compliment. This was near were I grew up. I was heartbroken to hear that he passed away so suddenly. My condolences to his family and his lab. I just know he's arguing about polio upstairs.

Slide from one of Claudia's thesis committee meetings (shared with her permission)

Photos from Claudia Lovell's PhD thesis defense, remembering Dr. Cancro (images shared with permission from Claudia and her PhD advisor, Dr. Montserrat Anguerra.)

Mike is the reason I initially got hired at Penn on February 13, 2006. When I asked him why he hired me over the other hundreds of other applicants, he said the words flight attendant stuck out at him. His reasoning... "if you can handle a crisis 10,000 feet in the air, you can handle just about anything on the ground". I only spent one and half years with Mike, but learned a great deal from him. Some of my core beliefs working in academia came from him. It was a rocky year and a half, but one that I value and carry with me everyday. I can truly say his legacy will go on.

My thoughts and prayers are with Jamie, Robyn, and Polly. My heart hurts for his lab and his current students. I cannot imagine their uncertainty, but know you all will be fine!

Rest in peace, Mike.

Copy of my remarks at Penn remembrance session:
Mike was a Professor in the Department of Pathology and Laboratory Medicine at Penn for almost half a century. I first met Mike 37 years ago, which I guess dates me as well. He interviewed me for admission to grad school. I still remember our conversation—it was about how difficult it was to disprove something. It was a hybrid between the practical questions every scientist faces sooner or later—how far down this rabbit hole do I go before I give up—and deeply philosophical aspects of how to pursue research questions.

A few months after that I was in medical school taking first-year Immunology. At that time Mike taught the entire course. He gave all the lectures and taught one of the small group sections. I was lucky enough to be in his small group section, but after the second class he tried to throw me out. He pulled me aside and abruptly said, “You took Immunology in college. What book did you use?” I didn’t remember the name but did recollect that it was a rather large tome with a dark blue cover. “That’s Paul’s Fundamental Immunology—you don’t need to be here.”

“But I want to be here!” I had responded and then followed the bizarre reverse negotiation where I asked him if I could stay in his class and had to justify my request! He agreed and I was very happy to be allowed to stay.

A few years after that I was deciding on a thesis lab. I went to Mike for advice. He took me outside- we walked around the bio pond and weighed my options. He helped me make the right choice. It was one of the most important decisions of my scientific career.

Mike was on my PhD thesis committee. He undoubtedly advocated for me in countless ways when I joined the faculty. And he always seemed to show up at pivotal moments to nudge me in the right direction.

As a new faculty member, I was put in charge of helping to organize the IGG retreat. I realized after talking to Mike that one of the most, perhaps THE most, important aspects of this job was getting the booze, and in particular making sure that there was stout beer—Guinness—for Mike!

Also, fairly early in my career, I was at a Keystone B cell meeting. It was one of the first meetings where I was chairing a session. Disaster had struck. One of my speakers had cancelled 10 minutes before the session was slated to begin. As I stood on the stage during the coffee break wondering what to do, I looked out into the audience and there was Mike. I ran up to him and asked him if he could pinch hit for me and he did. In ten minutes he put together some slides and gave a beautiful short talk. It is so hard to do that—I still marvel at how good he was at doing that.

Mike was a superb scientist and made seminal contributions to the field of B cell biology, but to me his most impressive accomplishments were in the areas of teaching and mentoring. Only a few weeks ago, I attended a thesis committee meeting with him where he was giving just one amazing suggestion after another and I thought to myself at the time, as I watched the student and her mentor both furiously writing down his suggestions, what a gift! Mike had the ability to give you all of his attention—I mean really all of it—and then he would ask you questions until he thoroughly understood the problem—and then he would ask questions and provide comments. He gave so freely of all of his ideas and was such a role model in this regard.

I know we all miss him dearly. But we can take solace in the fact that he taught each of us many things. Now we have the chance to share some of those teachings with the next generation of immunologists. In that way, he will live on in all of us.

To Mike Cancro’s family, friends, and colleagues.

It is with great sadness that we write to express our heartfelt condolences on the passing of Professor Mike Cancro. For many years, Dr. Cancro's work and dedication in the field of immunology have been an inspiration to us all, and his collaboration with colleagues here at GSK has been instrumental in advancing our understanding of BAFF biology, B cell tolerance and Age-associated B cells. His pioneering work with B cells has left a significant mark in the field, fostering breakthroughs that will continue impacting research for years to come. His commitment and passion for science was obvious from our interactions and we were fortunate to have witnessed his extraordinary dedication firsthand.

Please know that the entire team at GSK shares in your grief, and we extend our deepest sympathies to all who had the privilege of knowing and working alongside Dr. Cancro. His legacy will certainly continue through the invaluable contributions he made to science and through the lives and careers he impacted so profoundly.

Our thoughts and support are with you, and if there is anything we can do, please do not hesitate to reach out.

With deepest sympathy,
Robbie Henderson (on behalf of GSK team)

Mike making gnocchi with walnuts at Ann's (MA - 2019), demonstrating microscope care on lab cleanup day (2016), preparing for stand-up on some puzzling data at the IGG retreat (2018), toasting publication of Yi's paper (2011).

My deepest sympathies to Mike’s family and to the entire Penn and broader Immunology communities. Mike was my mentor and friend for the past 25 years. The time I spent in his lab is among the highlights of my life. He had a deep caring way about him and held the highest standards of integrity. Not only did he help refine my way of thinking and seeing the world around me, he also instilled a deep sense of responsibility for the banner we carry as scientists. We have an obligation to the truth, a responsibility to perform quality science, and a duty to share our data openly with the scientific community. As scientists, after all, we are charged with advancing the collective knowledge of the human race – a very noble endeavor! His scientific accomplishments speak for themselves. Yet, Mike took this charge one step further and made it his mission to help train the next generation of scientists. As one of his PhD students, I am a product of his teachings. I acknowledge that it is a huge privilege to be able to dedicate my life to the advancement of science, which is just one of the core beliefs Mike instilled in me. Through me and his other trainees, indeed everyone who has ever taken a class or attended one of his lectures, his memory lives on in our dedication to science and mentorship. I will miss him dearly.

I met Dr. Cancro at a Keystone meeting through one of his former students. From this meeting, it was easy to see his passion and commitment to science and to training the next generation of scientists. I wasn't his student, I didn't attend his university, he just wanted to know my story and encourage me to keep working. Science needs more people like Mike. My condolences to his family. His reach was as far as you can imagine.

I had the good fortune to work with Mike for a number of years at both Penn and NIH. He was a wonderful colleague, a wonderful guide for young students and scientists, and the best example of commitment to objectivity and excellence in scientific research.
My heartfelt sympathy for his family and associates. His loss will surely be felt in the research community.

I had the pleasure of working with Mike over the past few years on the NIH DP2 peer review committee. Mike was chairing these the last few cycles. The DP2 grants support innovative early career scientists. Just last year, Mike was chairing the three day, on-line discussions with enthusiasm, efficiency and care that was truly impressive. This is another example of Mike's commitment to early career scientists across the country! He will be missed at this year's DP2 review, which has been delayed, but is going forward! His many contributions leave a lasting legacy in the literature, his trainees and his wide positive impact on the culture of science. My condolences to family and friends.

Excerpt from letter from Dr. George Netto, Chair of Pathology & Laboratory Medicine: "This is an immense loss, and we will all mourn and honor Dr. Cancro in the days ahead.

Over his 49 years at Penn, Mike made an indelible impact. First and foremost, for Mike, was his science. Mike was a scientist’s scientist; he did science because he loved it and because it helped him communicate its power to others...His numerous research accomplishments were honored with multiple awards, including being named a Distinguished Fellow of the American Association of Immunologists and receiving the Lady Barbara Colyton Award for Autoimmune Research from PSOM.

Mike was a brilliant teacher. As a result, Mike received numerous distinguished teaching and mentoring awards throughout his career. He had a unique way of inspiring students and other trainees to realize their goals while also teaching them to have fun with their science along the way. Mike was a central force in the Immunology Graduate Group for decades inspiring hundreds of trainees. Indeed, Mike was known for asking the tough questions at prelim exams, and when the students received a pass, they knew that they had hit the mark...His dedication to mentoring and teaching is also evidenced by his long-standing role as a course director for an evening lecture course taken mainly by post-baccalaureate level students. Mike ran this course for some 25 years and showed no interest in ever letting it go.

Most recently, Mike served as the Vice Chair for Faculty Development and Academic Affairs in PLM. In this role, he was developing a curriculum for new faculty, helping them navigate the Penn research landscape with ease. His contributions to this curriculum will remain a lasting legacy. To the many faculty and trainees at Penn who had the privilege of knowing Mike, we have lost a cherished colleague, mentor, and friend. It is truly a profound loss."

Full text available here: https://pathology.med.upenn.edu/news/remembering-michael-p-cancro-phd

Excerpt from letter from Dr. Taku Kambayashi: "We all know the profound impact Mike had on Penn IGG (Immunology Graduate Group) and the global immunology community. Mike was the central force in IGG for decades, inspiring hundreds of faculty members and trainees. His contributions were invaluable, shaping both the field and the countless individuals who had the privilege of working with him. To me, Mike embodied the essence of an ideal professor. He was a dedicated academician, driven by pure intellectual curiosity and a deep-seated passion for contributing to the community. The precious moments I spent with Mike were invaluable, and I will honor his legacy by striving to emulate the remarkable person he was."

Excerpt from letter from Dr. John Wherry & Dr. Warren Pear: "Mike was an icon, a brilliant immunologist, and a foundation of our community. Mike’s 49-year legacy at Penn encompassed groundbreaking contributions to B cell biology, including defining transitional B cells, elucidating BLyS’s role in B cell selection, and discovering Age-Associated B Cells (ABCs). Moreover, Mike was integral in helping to nucleate Penn’s immunology community, including helping to found the Immunology Graduate Group, the core of our identity for approaching a half a century. His ability to bring together collaborations and foster scientific discourse helped establish Penn as a premier institution for immunology research. His significant contributions to Pathology department, Immunology Graduate Group and the broader I3H community have left an indelible mark on our scientific community and identity.

Mike was an exceptional mentor and teacher, earning the Charles Bernstein Lindback Award for Distinguished Teaching. He shaped countless careers through the Immunology Graduate Group and most recently served as Vice Chair for Faculty Development in PLM. His mentees, including Mark Shlomchik, Dave Allman, and Nina Luning Prak, have become leaders in immunology. Until his final days, Mike remained dedicated to mentoring and advancing immunology at Penn, recently completing a faculty teaching award nomination and ensuring research progress meetings continued.

Our community has lost a brilliant scientist, dedicated mentor, and dear friend. His impact on Penn’s scientific community and the field of immunology will endure through the countless lives he touched and the strong foundation he helped build at Penn."

My condolences to Dr. Cancro's family and friends. It has been almost 30 years since I took Dr. Cancro's immunology class at Penn Medicine - but I remember it like it was yesterday. Words really cannot describe how dynamic, effective and caring he was. To this day I describe our immune system (often to my young children when ill) in ways he taught - bringing an amazing biological system to bright and colorful light/life for all who had the privilege of his teaching. I distinctly remember almost abandoning my lifelong dream of become a medical physician to join a lab such as his - and pursue the wonderful immunology research he partook in. Suffice it to say - I continue towards clinical medicine but never forgot his passion for teaching and science. He was also such a kind and supportive mentor during a time in my own career when I need one. While our paths diverged - he was easily the most impactful teacher of my life - and the textbook he used is one of the few I've deemed worth saving over the many years. I am again, sorry to hear of his passing - but through the countless (literally) people he's impacted, his legacy will live on. I am grateful to have known him and appreciate the opportunity to share my own personal memories of this teaching legend. Thank you.

From 2013 to 2017, I had the privilege of being a postdoctoral fellow adjacent to Dr. Cancro’s lab. Dr. Cancro was not just an exceptional scientist and educator but also a mentor who always made time to share the rich history of immunology and guide young researchers in how to effectively discuss science. He generously read my K22 application and coached me on how to deliver an engaging chalk talk. His mentorship went beyond mere academic guidance; he was a profoundly honorable individual whose impact on my career and personal growth is immeasurable. I am forever grateful for his mentorship and the exemplary human qualities he demonstrated.