The likelihood that breast tumours will spread to the bone — a potentially deadly process — is enhanced when an immune-signalling pathway in the cancer cells is blocked.

Belinda Parker at the Peter MacCallum Cancer Centre in Melbourne, Paul Hertzog at Monash University in Clayton, both in Australia, and their team compared gene expression in cells from primary mouse breast tumours with those from bone metastases. They found that in the metastases, many genes sharing the same pathways as a protein called IRF7 were suppressed. This protein regulates the body's responses to an immune-signalling molecule called interferon, a version of which is used in the treatment of certain cancers. Restoring IRF7 signalling in tumour cells reduced bone metastases and boosted immune activity and metastasis-free survival time.

Patients with breast cancer and low expression levels of IRF7-associated genes in their primary tumours could be at higher risk of metastasis, the authors say.

Nature Med. http://dx.doi.org/10.1038/nm.2830 (2012)