Researchers in Israel have developed tiny drug-free particles that stopped the growth of one of the deadliest forms of breast cancer in preclinical studies, raising hopes for a radically different approach to cancer treatment.

The study, published in the journal ACS Nano, was led by Ph.D. candidate Ofri Vizenblit and colleagues at the Technion–Israel Institute of Technology under the supervision of Assistant Professor Assaf Zinger, head of the Bioinspired Nano Engineering and Translational Therapeutics Laboratory.

The research focused on triple-negative breast cancer, an aggressive disease that spreads quickly and is often difficult to treat because it lacks the common molecular targets used by many modern cancer drugs. Despite advances in chemotherapy and immunotherapy, patients with this form of cancer frequently face poorer outcomes than those with other breast cancer types.

Instead of attacking cancer cells directly, the Technion team targeted the tumour microenvironment—the complex community of immune cells, blood vessels, and supporting tissues surrounding a tumour. Scientists increasingly believe this environment plays a crucial role in helping cancers grow and evade the body's natural defences.

Cancer cells are known to manipulate macrophages, a type of white blood cell that normally protects the body from infection and disease. Once hijacked, these cells can help tumours survive and spread by suppressing immune attacks.

To counter this process, the researchers created nanoparticles called MPsomes. Acting as biological decoys, the particles compete with immune cells for key binding sites around tumours. Laboratory experiments and mouse studies indicated that the nanoparticles accumulated in unusually high concentrations around the cancer and significantly slowed tumour growth.

What surprised researchers the most was that the particles achieved results comparable to some advanced immunotherapies without releasing a drug, chemotherapy agent, or antibody.

“This is a conceptual shift,” the researchers explained. “The therapeutic efficacy does not stem from the release of an active substance but from the biological information encoded on the surface of the nanoparticle.”

In simple terms, the particles work by sending signals that alter how immune cells behave. The team found fewer tumour-supporting immune cells and more cancer-fighting immune cells in treated tumours. No signs of damage were detected in major organs during the experiments.

The findings add to growing international research exploring whether cancer can be controlled by reshaping its environment rather than destroying tumour cells directly. Scientists at institutions worldwide are increasingly investigating immune-system engineering and microenvironment-based therapies as potential next-generation cancer treatments.

However, experts caution that the work remains at an early stage. The technology has only been tested in mice, and many promising cancer therapies fail during human trials. Questions about long-term safety, effectiveness and regulatory approval remain unanswered.

“Although we focused here on a specific type of cancer," said Dr Zinger, “this discovery is a paradigmatic breakthrough that can lead to the development of new therapeutic platforms that are more effective and safer. I sincerely hope we will find the path to bring this invention to the clinic.”