Baylor University researchers engineered Listeria monocytogenes to act as a vector that invades colorectal tumors and delivers cytotoxic proteins directly into cancer cells. The study shows the modified bacterium can transport therapeutic payloads into tumor tissue, enabling localized protein-based killing of malignant cells in preclinical models. The approach leverages Listeria’s innate invasive biology to bypass some barriers of systemic delivery; investigators emphasize engineered safety controls and payload specificity. The team frames the platform as a potential complement to existing immunotherapies and targeted agents, pending further safety and dosing work.