Background

Each year, about 80,000 people in the United States are told they have bladder cancer, and around 17,000 die from the disease. The most common type is called urothelial carcinoma, but it often appears together with other, less common types of bladder cancer. These “variant” types look and act differently under the microscope. Unfortunately, these uncommon forms tend to be more aggressive and don’t respond well to standard chemotherapy. Scientists don’t yet fully understand the genetic changes that cause these cancers, and there haven’t been enough good lab models to study them closely. 

What the Study Proposes to Address

To fill this gap, researchers have developed a new and faster way to study the genes involved in bladder cancer. Using this approach, they have already been able to create lab models that mimic not only the common urothelial carcinoma but also several rare and aggressive forms—such as squamous cell, sarcomatoid, and plasmacytoid bladder cancers. These new models are especially valuable because few existed before. The researchers will now work to identify which specific genes are most important for starting and keeping these variant cancers growing. They will also compare the detailed molecular make-up of their lab models to that of real human tumors to better understand what drives these cancers. In addition, they plan to study how the immune system interacts with these cancers and whether combining immunotherapy with chemotherapy could help stop tumor growth. 

Why This Research is Important

This work has the potential to greatly expand what scientists know about the most difficult types of bladder cancer. By pinpointing which genes and molecular pathways matter most, researchers may uncover new targets for treatment and help doctors predict which therapies might work best. The new lab models created through this study will also serve as an important resource for testing new drugs in the future. Ultimately, this research could speed up the development of better, more personalized treatments for patients facing aggressive forms of bladder cancer. 

Final Report Summary

Researchers have created a new system that allows them to quickly develop mouse models of bladder cancer. These models closely resemble the many different forms of bladder cancer found in people, making them valuable tools for research. 

Using these models, the team discovered that a protein called PPARG plays an important role in how bladder cancer begins. They found that having either too much or too little of this protein can actually stop tumors from forming, showing that the right balance of PPARG is necessary for cancer to grow. 

The scientists are now studying PPARG more closely to better understand how it influences bladder cancer. These new mouse models will help researchers explore how the disease develops and test new treatments more effectively, bringing them one step closer to finding better therapies for patients. 

Li, S., Wong, A., Sun, H., Bhatia, V., Javier, G., Jana, S., Montgomery, R. B., Wright, J. L., Lam, H. M., Hsieh, A. C., Faltas, B. M., Haffner, M. C., & Lee, J. K. (2023). Combinatorial genetic strategy accelerates the discovery of cancer genotype-phenotype associations. bioRxiv : the preprint server for biology, 2023.04.12.536652. https://doi.org/10.1101/2023.04.12.536652

Department of Defense Peer-Reviewed Cancer Research Program Impact Award mechanism, “Defining new vulnerabilities of variant histology bladder cancer.”, $1,664,994

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