Accurate removal of tumors is one of the most critical aspects of cancer surgery, but it remains a major challenge in clinical practice. In breast cancer, for instance, up to 35% of patients have positive margins after surgery, meaning cancer cells are left behind, thus often requiring reoperations and increasing the risk of recurrence.

Preoperative imaging and ultrasound frequently fail to fully delineate tumor boundaries, leaving surgeons to rely heavily on experience. These limitations underscore the urgent need for real-time, intraoperative visualization technologies to guide tumor resection more precisely. Now, researchers have developed a new solution that uses fluorescent signals to illuminate tumors during surgery, improving accuracy and reducing surgical burden.

The next-generation intraoperative imaging platform developed jointly by the Korea Institute of Science and Technology (KIST, Seoul, South Korea) and Chungnam National University Hospital (Daejeon, South Korea) is based on engineered bacteria. These beneficial bacteria emit fluorescence specifically at tumor sites, acting as a contrast agent that illuminates tumors like a neon sign during surgery.

The fluorescent bacterial system activates only within tumor tissues, highlighting their locations and margins in real time. The signal remains stable in vivo for over 72 hours and is visible to the naked eye even under standard surgical lighting. The bacteria are designed to respond to two universal tumor microenvironment traits—hypoxia and immune evasion—making the system broadly applicable across various solid tumors.

The platform uses near-infrared light, produces fluorescence five times stronger than conventional agents, and is compatible with existing surgical endoscopes, imaging tools, and robotic systems, enhancing precision and reducing operation times. Validation studies showed strong performance in visualizing tumors within complex internal organs.

The technology, featured on the front cover of Advanced Materials, can integrate with hospital-based fluorescence-guided surgical systems, further strengthening its commercialization potential. Researchers plan to expand the platform into a comprehensive cancer treatment system that includes diagnosis, surgery, and therapy. They are also exploring its use as a drug delivery system by leveraging the bacteria’s tumor-targeting capabilities, with ongoing work in precision drug delivery and clinical safety evaluations to support future applications.

"This study demonstrates a novel approach in which bacteria autonomously locate tumors and emit fluorescent signals, allowing real-time identification of tumor location and boundaries during surgery. Its applicability across a range of solid tumors positions it as a potential new standard for precision surgical imaging," said Dr. SeungBeum Suh, KIST researcher and co-lead of the study.

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