Many cancer studies focus on the genetic changes in a tumor that may influence its development or identify potential targets for new treatments. But a growing number of researchers have been looking into a different factor that might affect how tumors behave: bacteria. Several studies have suggested that the mix of bacteria in the gut of people with cancer—their gut microbiome—can affect their immune system’s ability to recognize and attack tumors or the effectiveness of some cancer treatments. Now, results from a new study suggest that, in the case of people with pancreatic cancer, the makeup of bacteria that populate their tumors could predict how long they live. Experiments in mice conducted as part of the study also pointed to the possibility that fecal transplants—which are primarily used to treat people with a serious infection with a particular type of bacteria—might have potential as a way to treat pancreatic cancer. Findings from the NCI-supported study, led by researchers at the University of Texas MD Anderson Cancer Center and Johns Hopkins Kimmel Cancer Center, were published August 7 in Cell. Based on the results, an early-stage clinical trial is being planned to test fecal transplants in people with pancreatic cancer. While the study’s findings are encouraging, said the study’s lead investigator, Florencia McAllister, M.D., of MD Anderson’s Department of Clinical Cancer Prevention, she cautioned that it’s still too early to say what will come of them. At the same time, Dr. McAllister added, the findings point to wide-ranging possibilities for altering the tumor microbiome in people with this highly fatal form of cancer. “I think it’s something that could have an impact on any strategy that’s being thought about for pancreatic cancer treatment,” she said.