By Anna Greene, PhD, NETRF Chief Scientific Officer
Drugs like Ozempic®, Wegovy®, and Mounjaro®, known as GLP-1 receptor agonists, are now widely used to treat type 2 diabetes and obesity. They work by mimicking a natural gut hormone that helps control blood sugar, slows digestion, and reduces appetite.
As these medications become more common, some people who take them will also have neuroendocrine neoplasms (NENs), tumors that start in hormone-producing cells. That overlap raises an important question: could GLP-1 drugs also affect tumor cells?
A new lab study by Po Hien Ear, PhD, and Andrew Bellizzi, MD, along with their team at the University of Iowa and collaborators at the University of Texas MD Anderson Cancer Center, was recently presented at NETRF’s 2025 Marie & Robert E. Petersen Neuroendocrine Tumor Research Symposium (Watch the presentation beginning at 19:20 minutes into the session recording.) It doesn’t provide final answers, but it offers important early clues about how GLP-1 drugs might interact with different types of NENs.
What did the researchers study?
The team studied 576 neuroendocrine neoplasms, including neuroendocrine tumors (NETs) and neuroendocrine carcinomas (NECs), from many different parts of the body and asked a simple question:
Do these tumors have GLP-1 receptors—the “docking stations” that GLP-1 drugs need to work?
They also grew tiny 3D “mini-tumors” from patients’ duodenal, ileal, and pancreatic NETs and exposed them to semaglutide, a commonly used GLP-1 drug, to see how the cells responded
What did they find?
Only about 7% of all the tumors tested had GLP-1 receptors.
Receptors were found in some duodenal, gastric, pancreatic, and lung NETs, as well as in some pheochromocytomas. When the researchers treated duodenal NET spheroids (which expressed GLP-1 receptors) with semaglutide in the lab, those cells activated a growth pathway and grew more over 2 weeks.
In contrast, several common NET types showed no GLP-1 receptors at all in this study. That included ileal (small intestine/small bowel) NETs and medullary thyroid carcinoma (the thyroid NET that’s specifically mentioned in current GLP-1 drug warnings). Additionally, the neuroendocrine carcinomas tested did not express the GLP-1 receptor. Spheroids made from ileal NETs, without receptors, did not grow more when exposed to semaglutide.
Put simply, in the lab, GLP-1 drugs only “fed” tumor cells that had the GLP-1 receptor. Tumor cells without the receptor didn’t seem to react.
What does this mean for patients?
It’s very important to stress: this was a laboratory study, not a clinical trial. It does not prove that GLP-1 drugs make NENs grow, or that they are safe, in real patients. But it does suggest that:
- Only a small fraction of NENs may even have the “docking station” (the GLP-1 receptor) that these drugs can act on.
- Among those that do, especially some duodenal and pancreatic NETs, there may be a potential for GLP-1-driven growth that deserves more research.
As Dr. Bellizzi adds, “GLP-1 receptor agonist usage is so pervasive—that we’re increasingly encountering NET clinician and patient anxiety on safety. We hope this study provides some reassurance, especially to ileal NET patients on pure GLP-1 receptor agonists. We’re excited to keep working on this story.”
For now, this study is a signal, not a verdict.
What should you do if you have a NEN and use a GLP-1 drug?
First and foremost: don’t stop your medication on your own. GLP-1 drugs can be very helpful for diabetes, weight, and heart health, and stopping suddenly can be risky.
Instead, use this study as a starting point for a conversation with your care team. Ideally, talk with both:
- Your NEN specialist or oncologist, and
- The clinician who prescribes your GLP-1 drug
Ask how your specific tumor type and overall health fit into what’s known so far, and whether there are alternative options if needed.
NETRF’s perspective
At NETRF, we see this study as an important early step. It highlights that:
- Not all neuroendocrine neoplasms are alike at the molecular level.
- Some may be sensitive to GLP-1 signaling; many may not.
Most of all, it shows why we need more research, especially clinical data, to understand how GLP-1 drugs affect people living with NENs.
We’ll continue to follow this evolving area closely and share new information so that you and your care team can make the most informed, personalized decisions possible.