Uncommon Cancers, Common Goals: Overcoming the Challenges of Rare Cancer Research

June 23, 2026 by

Although any single type of rare cancer affects very few people—by definition, a rare cancer is one with an incidence of fewer than 6 cases out of every 100,000 people per year—in the aggregate, they collectively account for more than 25% of all cancer cases. Taken as a group, rare cancers are paradoxical—on their own, so infrequent as to make study and treatment difficult, but together, a sizable burden affecting a significant portion of all cancer patients. Each one of those patients still requires therapies that require research progress for their specific indications, regardless of whether that patient has gallbladder cancer, male breast cancer, hairy cell leukemia, or any one of another dozens of rare cancer subtypes.

However, the relative scarcity of cases and data at the level of individual cancer type makes rare cancers a uniquely challenging area of scientific investigation—a problem compounded by the underinvestment in rare cancer research compared with the resources dedicated to the most common cancer types.

That’s why the American Association for Cancer Research (AACR) will be dedicating a meeting to the topic this summer. At the AACR Special Conference in Cancer Research: Breaking Barriers in the Fight Against Rare Cancers, to be held July 18-20 in Vancouver, Canada, scientists will be tackling rare cancers head-on through a variety of sessions that will cover lessons learned while proposing promising future directions for the field.

Cancer Research Catalyst spoke with the cochairs in advance of the meeting to learn what excites them as they prepare for this first-of-its-kind conference from AACR. Cochairing the conference are the following esteemed researchers:

Throughout the course of seven plenary sessions, special sessions, and panel discussions, the meeting will cover a variety of issues. These range from special topics of investigation—such as genomic drivers of rare tumors and progress in adapting immunotherapy for rare cancers—to proposals for inter-institutional collaboration and new resources for improving rare cancer research. Additionally, AACR Project GENIE® will deliver a special presentation focused on the wealth of data available in the registry to conduct rare cancer research. Finally, the conference will conclude with a plenary session exploring innovations in clinical trial design for rare cancers.

What is a challenge in rare cancer research you hope to see addressed at this meeting?

Futreal: Clinical trial design in rare cancers is a big issue and one that I’m excited to see discussed at this meeting. New trial designs are critical to moving progress in rare cancers forward, because we need novel therapies. There’s some exciting thinking about more basket trials that enroll patients based on shared common molecular features or clinical phenotypes—moving beyond histological tumor type as the defining element.

I also believe that, as a community, we need to focus on collecting and centralizing what might be called “real-world data,” to gather the information necessary to create synthetic cohorts. By assembling real-world data from comparable patients in other trials and in standard care or best available care settings, we can create virtual or synthetic control arms that allow us to make treatment comparisons in our trial with confidence. And that is something I think we need to be doing more of in rare cancer research, because with so few patients for a given disease, standard clinical trial thresholds just won’t get met—which means limited progress toward therapies. We need to leverage creativity, computation, and resources to perform the quality research needed for these patients and advance the field.

For example, we can collaborate with regulatory institutions to work toward understanding how we can utilize limited signals from relatively small trials. Ultimately, we need to do whatever we can to move novel therapeutics forward and develop better therapies for patients, because many patients with rare cancer essentially don’t have good options at the moment.

How are improvements in technologies benefiting rare cancer research?

Taran Gujral, PhD

Gujral: We live in an era defined by a vastness of data—of what we generate and what we analyze. That’s true for common cancer, and even though we necessarily have less data on rare cancers, we can still glean a remarkable amount of data from every sample. As molecular profiling of patient samples becomes the standard, the quantity and quality of rare cancer data at our disposal will only increase.

There’s still more progress to be made. At any given cancer center, one may never encounter enough cases of a particular rare cancer to evaluate a research question. But mining rare cancer data from every patient and from different institutions can greatly expand the limits of what we can investigate. Through collaboration, we can achieve statistically powerful approaches to many rare cancers.

Howitt: I am not an artificial intelligence (AI) expert, but the advances in what AI is capable of are remarkable. We now generate multiomic data for relatively little cost compared to how expensive it used to be, and AI or machine learning methodologies help us make sense of the many thousands or millions of features that we’re looking at.

In rare cancer research, we’re moving toward integrating as many modalities as we can—whole-genome, whole-transcriptome, proteomics, glycoproteomics—and I think that inevitably requires AI integration.

Tan: Our ability to study, characterize, and interrogate rare cancers has been greatly accelerated by the advent of new data analytics, bioinformatics, and computational biology approaches.

For example, we now have the ability to use new technologies that characterize DNA changes with base-pair precision. Evaluating transcriptional changes and epigenetic changes with such detail allows us to look through a multimodal lens to identify critical drivers of rare cancers, which provides us with invaluable targets.

This has not been possible in the past, and by amassing this information from different countries and different communities, we can begin to look at the aggregate and study common features among rare cancer types.

Can you give our readers a sneak preview of what you plan to discuss during your talk?

Futreal will present “Eliminating ‘luck’ – learning from rare cancer patients to improve outcomes,” during the session,“From Bench to Bioinformatics: Advanced Modeling of Rare Cancers.”

Andrew Futreal, PhD, FAACR 

Futreal: I developed this talk based on a concept that evolved from my discussions with patients. One individual comes to mind who had a stage 4 rare cancer and lived well beyond what the statistics would have predicted for them.

When I spoke with this patient, they said to me, “I got lucky.” And on some level that makes sense—other patients in comparable positions succumb to disease relatively rapidly, despite every effort we make.

But I want to push back against the notion that it’s a matter of luck. When we can’t stop cancer from progressing, that stems from an incomplete understanding of the nature of the disease in that patient’s instance.

We have the data and the tools, particularly now, to dismantle this idea of luck when it comes to cancer, even its rarest forms. As researchers, we can and should tease apart trajectories and probabilities for different patients; we can assert responsibility over what we call “luck.”

Gujral will present “Functional precision oncology in rare cancers: From biobank to drug discovery,” during the session, “From Bench to Bioinformatics: Advanced Modeling of Rare Cancers.”

Gujral: One of the challenges of rare cancer is that, as researchers, we lack preclinical models to study rare cancers or to investigate their key drivers and molecular mechanisms. Establishing a biobank focused on rare cancer is one of the main focuses of my lab, and it’s something I want to explore at this meeting.

Another key question I want to raise is: How do we preserve rare cancer specimens from any patient, anywhere in the United States so that we can go back to those clinical samples and profile them molecularly, trying to understand—what are the key mutations or key drivers? And how do we use that material to develop new models?

We can come together as a community to develop a resource that could be shared across institutions, especially for rare cancers where you see a few dozen patients in a year. Once we have these resources, we can start to ask questions and leverage our data across institutions as we work toward therapies.

Howitt will present “Challenges and updates in the classification of uterine mesenchymal tumors,” during the session, “Diagnostic Challenges and Novel Classification Strategies in Rare Cancers.”

Howitt: Uterine mesenchymal tumors are, historically and currently, very challenging. These tumors come in many different forms that demand appropriate diagnostic categorization.

We need to understand the tumors’ underlying biological behavior, because that’s how we make critical determinations about which organs to remove, whether patients should receive chemotherapy, and so on. With so much hinging on a pathology report, that question of classification becomes very critical.

Brooke E. Howitt, MD

However, many uterine mesenchymal tumors don’t have a very specific or defined molecular marker that we can use clinically, and, as such, they become very difficult to reproducibly diagnose. And without consistent diagnoses, we struggle to develop and assess prognoses.

In my lab, we applied methylation profiling, as has been done in many tumor types, to rare uterine mesenchymal tumors. We wanted to see if we could get a better handle, or at least another angle, on the classification of these tumors—and indeed, we can pull out prognostically significant subgroups using this kind of extra layer of profiling.

How do advances in rare cancer research impact cancer research in general?

Gujral: For rare cancer researchers, much can be learned from the decades of research from common cancers, but the reverse is also true. Rare cancer researchers necessarily push boundaries and challenge paradigms because there is a fundamental constraint in some sense.

When you know that it might not be amenable to run a phase III trial in a very small patient population, you have to get creative. So the approaches being developed by rare cancer researchers thinking about translation challenges have the potential to deliver benefits beyond their original applications.

Howitt: In general, the better we can do rare cancer research, the better we do all cancer research. As a researcher, when you find a molecular feature or target in rare cancer, you unveil a potential marker or target that you can also investigate in common tumors—possibly even common tumors that were misdiagnosed.

Novel targets always have the potential to occur in more than just one cancer type, rare or common. So I think that expanding and diversifying research in these rare cancers is only going to help all cancers when it comes to diagnostics, therapeutics, and patient outcomes.

What do you hope attendees will take away from this meeting?

Futreal: I want to reiterate my excitement about the matter of clinical trial design, just because I think it’s such a critical issue, and the meeting is an excellent opportunity to unite researchers in tackling that challenge.

Patrick Tan, MD, PhD

I also think that attendees will benefit from the questions the conference will raise about the role of immune modulation in rare cancer. Immunotherapy has revolutionized treatment for multiple common cancers, and I think the developing applicability of immunotherapy to rare cancers is quite promising.

Attendees will also have the opportunity to engage with the question of rare cancers’ deep immune biology. That is, I think, hugely important to move the field forward with therapies and technologies that are already in use for common cancers.

Tan: Firstly, we hope that by participating in this collective conference on rare cancers, attendees will find that they are part of a larger community that shares common opportunities and common challenges. We can break these barriers by coming together and engaging in productive conversations with one another.

I also hope that these new conversations and connections will enhance our collective appreciation for rare cancer research to contribute to the greater fight against cancer in all its forms. In showing that AACR takes rare cancers very seriously, this conference can unite cancer researchers behind the need to address the pivotal challenge of rare cancers—a field where progress can pay dividends across a wide array of research areas.

The AACR Special Conference in Cancer Research: Breaking Barriers in the Fight Against Rare Cancers will be held July 18-20, 2026, at the JW Marriott Parq Vancouver in Vancouver, British Columbia, Canada.

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