Cancer immunotherapies have transformed treatment for many cancers, but pancreatic cancer remains especially difficult to treat. One major reason is that pancreatic tumors often create a “cold” tumor microenvironment, where the tumor prevents immune cells from mounting a strong attack.

In a new study published in Science Advances, researchers at the University of Chicago report a promising new strategy to overcome this barrier using BifidoSumIL-2, an engineered bacterial strain of Bifidobacterium longum, a probiotic bacterium naturally found in the gut, to deliver an immune-stimulating therapy directly inside tumors.

The treatment suppressed pancreatic tumor growth by selectively activating cancer-fighting T cells. The effects were further enhanced when combined with chemotherapy, radiotherapy or immunotherapy. The study highlights BifidoSumIL-2 as a potentially powerful approach for improving treatment response in pancreatic cancer.