Certain types of breast tumors can send signals that freeze the growth of their own secondary cancers, according to a major new study co-led by Australia’s Garvan Institute of Medical Research.

The findings, uncovered in mice and patient tumors, are published in Nature Cell Biology today. They reveal a previously unseen ‘ecosystem’ in advanced breast cancer, in which the primary breast tumor emits signals that halt the growth of secondary tumors elsewhere in the body.

The spread of cancer beyond the original tumour—known as metastasis—is the most deadly aspect of most cancers. Once a breast cancer has spread to other parts of the body, treatments are far less effective and a patient’s prognosis worsens sharply. In Australia, 8 women die from breast cancer every single day.

“This new research has yielded that rare thing,” says Dr Christine Chaffer (Garvan), “—a clue from the cancer itself about new possibilities to fight its spread. Our goal is to work out how we can mimic this ‘freezing’ of secondary cancers, so that one day we might influence all breast cancers to keep their secondary tumors in check.”