The spread of certain breast cancers to bones can be driven by an enzyme called lysyl oxidase (LOX), reports a study in Nature.

This finding reveals a potential biomarker for predicting the risk of bone metastasis, and may facilitate the development of preventative treatments. 

Metastasis of breast cancer to the bone affects approximately 85% of patients with advanced disease and is a major cause of deaths from breast cancer, but the molecular interactions responsible for this spread have been unclear.

Janine Erler, Alison Gartland and colleagues provide new insights into this process in a particular subset of breast cancers (called oestrogen receptor negative (ER−) breast tumours), establishing a link between bone metastasis and the secretion of LOX in patients with ER− breast cancer.

They find that oxygen-deprived breast cancer cells release high levels of LOX, and demonstrate that this enzyme drives the degradation of bones, producing lesions that are a favourable environment for circulating tumour cells to colonise.

Introducing LOX into tumour-free mice is also shown to cause bone degradation, but treating these mice with zoledronic acid (a drug used to treat osteoporosis) prevents the formation of bone lesions.

The authors propose that similar treatments in patients with breast cancers that express high levels of LOX might block the establishment and growth of tumour cells within the bone.

Source: Nature