The technique, which appeared to successfully stop the spread of breast cancer in mice, was unveiled by scientists from the Cold Spring Harbor Laboratory, Dana-Farber Cancer Institute, Stony Brook University, and a host of other research institutions in the journal Science Translational Medicine on Wednesday.

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Next-generation cancer fighting therapies on the market today use the body’s immune system to combat tumors, as does experimental technology like CRISPR gene-editing. But the new nanotech has a different target: The cells that actually help cancer metastasize and spread throughout the body.

These immune cells, which are meant to ward off infections, create structures called neutrophil extracellular traps (NETs) that help them fight bacteria. But NETs can actually wind up helping spread the cancer by creating tissue openings that cancerous cells can exploit, study co-author Mikala Egeblad explained to Vice.

So the researchers created a new particle coated with a special enzyme that can kill these cells before the cancer can use them to metastasize. The results were modest, but promising: Three out of the nine mice given the nanoparticle showed no evidence of breast cancer progression, while all mice in the control group continued to worsen.

Still, there are important questions about how effective such a technique might be in humans. NETs are meant to combat bacteria, after all, and destroying them might make cancer patients whose immune systems are already compromised even more vulnerable to infection.