A major breakthrough in the hunt for a breast cancer cure has been made after scientists discovered how to stop the disease spreading.
They have identified the enzyme that promotes the spread – changing the tumour from a single, more treatable one, to a number of separate cancers threatening other organs.
If drugs can be created to block the enzyme, thousands of lives could be saved every year.
Arlene Wilkie, director of research at Breast Cancer Campaign, said: “Although we can treat breast cancer that has spread, we cannot cure it.
“This laboratory research shows great promise and we look forward to seeing how it translates into patients.”
Cancer can often be treated and even cured if caught at an early stage.
But there is no treatment or way to prevent the spreading – or “metastasis” – of cancer in the later stages.
According to lead researcher, Dr Janine Erler, from the Institute of Cancer Research, more than 90 per cent of cancer deaths are because the disease has spread to other organs.
Secondary tumours are notoriously hard to treat. Breast cancers are known to spread to lymph nodes, the bones and the lungs.
Once metastases are detected in a breast cancer patient, the average survival is less than two years.
In her study, published in the journal Cancer Research, Dr Erler found that the enzyme lysyl oxidase-like 2 – or LOXL2 – is needed for tumour cells to escape from the breast and invade surrounding tissue.
Dr Erler said: “Around 12,000 women die from breast cancer in the UK each year, most because their cancer has spread to other parts of their body.
“Our study shows that inhibiting the action of LOXL2 can significantly reduce the spread of breast cancer, suggesting that drugs which block this enzyme may be effective in preventing patients’ cancer from spreading.”
LOXL2 has also been linked to the progression of colon and oesophageal cancer.
The UK has the 11th-highest breast cancer rate in the world, with 47,000 new cases diagnosed each year.
Recent studies showed that British women have a one in eight chance of getting the disease.