Scientists have discovered why breast cancer cells that have spread to the lungs may ‘wake up’ following years of sleep – forming incurable secondary tumours.
Patients with oestrogen receptor positive (ER+) breast cancer – the most common type – have a continued risk of their cancer recurring in another part of their body for many years or even decades after their original diagnosis and treatment.
The new research shows how molecular changes within the lung that occur during ageing can support the growth of these secondary tumours, but that an existing cancer drug can reduce this growth.
Dr Simon Vincent, Director of Research, Support and Influencing at Breast Cancer Now, said: “With an estimated 61,000 people living with secondary breast cancer in the UK, more research to understand and treat it is vital.
“This exciting discovery brings us a step closer to understanding how we can slow down or stop the development of ER+ secondary breast cancer in the lung. It has the potential to benefit thousands of women living with this ‘time bomb’ in the future, ensuring fewer patients receive the devastating news the disease has spread.”
Existing cancer drug reduced growth
The team at The Institute of Cancer Research, London, found that if the level of PDGF-C protein increases, which is more likely in an ageing lung or when its tissue becomes damaged or scarred, it can cause the dormant cancer cells to grow and develop into secondary breast cancer.
Working with mice with ER+ tumours, the researchers targeted PDGF-C signalling with an existing cancer growth blocker called imatinib, which is currently used to treat patients with chronic myeloid leukaemia.
The mice were treated with the drug both before and after the tumours had developed. For both groups, the cancer growth in the lung was significantly reduced.
Dr Frances Turrell, postdoctoral training fellow in the Division of Breast Cancer Research at The Institute of Cancer Research, London, said: “We now plan to better unpick how patients might benefit from the existing drug imatinib, and in the long term aim to create more specific treatments targeted at the ‘reawakening’ mechanism.”
