Scientists identify protein used by breast cancer tumours to recruit normal cells and promote cancer spread

Researchers at The Institute of Cancer Research have discovered that more aggressive forms of breast cancer secrete a protein called Wnt7a which recruits and mutates surrounding cells to promote the spread of the disease. The team examined nearly 900 breast cancer samples and found that women who had high levels of Wnt7a were at higher risk of developing secondary cancer and had a decreased survival rate. In order to effectively spread around the body breast tumours trigger other non-cancerous cells which enter surrounding tissue and join the blood stream. The infected cells then move around through the blood cells and colonise distant tissue. It has long been known that breast tumours can infect non-cancerous cells but not known how they become mutated. Subsequent studies showed that blocking the production of Wnt7a in aggressive tumours reduced the likelihood of secondary cancer to the lung, while increasing Wnt7a production in less-aggressive tumour cells promoted invasion and spread. Professor Clare Isacke, Professor of Molecular Cell Biology and Academic Dean at The Institute of Cancer Research, London, said: “Our research showed that women whose breast cancers secreted a greater amount of Wnt7a were much more likely to see their disease spread to other parts of the body, at which point it unfortunately becomes incurable. “We urgently need to stop tumours recruiting and activating non-cancer cells by secreting this Wnt7a protein, It is now clear that effective anti-cancer strategies will also need to target the cross-talk between cancer cells and normal cells, and we believe this could be a particularly promising avenue for new treatments in the future.”