Grant funds research evaluating gut microbiome’s role in pancreatic cancer


Ryan M. Thomas, M.D.
Ryan M. Thomas, M.D.

Ryan M. Thomas, M.D., an assistant professor in the UF College of Medicine Department of Surgery, has received a Mentored Scholar Research Grant from the American Cancer Society to continue his investigation into the role of the intestinal microbiome in pancreatic cancer growth and development.

The $722,000 grant provides five years of funding and is an interdepartmental collaboration with his research mentor, Christian Jobin, Ph.D., in the UF Department of Medicine.

Pancreatic cancer is now the third-leading cause of cancer death in the United States, but progress on screening and treatment has been slow and novel research is necessary. Pancreatic ductal adenocarcinoma, or PDAC, is the most common and lethal form of the disease.

There are few known risk factors for pancreatic cancer, and most people with PDAC appear to develop the disease spontaneously, Thomas noted.

“The microbiome and its bacteria are unique in each person,” Thomas said. “There are trillions of bacterial cells that share a person’s body space. For the most part, it is a symbiotic relationship but a balance between helpful and harmful bacteria exist.”

Emerging research, however, shows that the microbiome is associated with a variety of diseases, including cancer, but is a relatively uninvestigated area in pancreatic cancer research. Observational studies suggest that patients with PDAC have a distinct oral microbiome compared to patients without the disease but studies demonstrating causation are lacking, he explained.

Thomas hypothesizes that the intestinal microbiome can influence the development of PDAC. Additionally, bacteria in the gastrointestinal tract can affect inflammatory processes both inside and outside of the intestines.

“Microscopically, pancreatic cancer is made up of inflammatory products, which raises the possibility that the microbiome plays a key role in initiating or perpetuating pancreatic cancer growth,” Thomas said.

His current project builds on preliminary data that demonstrate mice given antibiotics to eradicate the intestinal microbiome show decreased formation of PDAC and slower tumor growth. It will further identify specific bacterial classes and species that are responsible for these observations and investigate signaling pathways that are involved using germ-free technology and a variety of mouse models of pancreatic cancer.

He added that his interest in the disease is both academic and personal.

“My grandmother was diagnosed with pancreatic cancer while I was a general surgery resident. She is the motivation that keeps my research in the disease going,” he said. “She passed away within four months of her diagnosis. At that time, and even now, pancreatic cancer funding and research is limited.”

If his research proves successful, Thomas hopes that it will lead to clinical trials in humans and eventual treatment and prevention of pancreatic cancer.

“Ideally, in the future, we will be able to identify patients at risk for pancreatic cancer just based on the makeup of their intestinal biome,” he said. “That would allow doctors to identify and alter patient-specific risk factors—enabling earlier detection and treatment, and improved survival.”

Ryan M. Thomas, M.D., is supported by the American Cancer Society —  Norma and Rich DiMarco Mentored Research Scholar Grant (MRSG-17-228-01-TBG).