Escherichia coli Nissle 1917 in Cancer Bacteriotherapy: Functional Applications and Translational Challenges

Abstract Cancer bacteriotherapy has emerged as a strategy to exploit the natural ability of bacteria to interact with tumor tissue, but its development remains limited by the need to balance microbial activity with safety. Escherichia coli Nissle 1917 (EcN) has gained increasing attention as a probiotic bacterium that can be engineered for biological modulation, metabolic conversion, and hybrid therapeutic systems. This review discusses EcN in cancer therapy, focusing on its biological properties, tumor-colonization behavior, functional applications, and translational constraints. Overall, EcN offers a versatile framework for localized therapeutic strategies, but its clinical relevance will depend on better control of bacterial survival, therapeutic activity, and clearance.