CANCER RESEARCH UK scientists have used a cutting edge microscopy technique to identify genes whose activity could be blocked by drugs to stop the spread of the breast cancer. The research is published in Nature Cell Biology*.
The scientists from Cancer Research UK’s London Research Institute and Breast Cancer Campaign analysed the role of cell ‘messengers’ controlled by Transforming Growth Factor Beta (TGF-beta) – which regulates cell growth and movement – to see how it affected the spread of breast cancer cells in mice.
A ‘reporter’ protein in the cancer cells glowed blue when the TGF-beta cell messenger system was active.
The findings showed that TGF-beta controlled a set of genes that need to be first turned on and then off to enable breast cancer cells to spread through the blood.
An understanding of how cancer cells spread will help scientists design treatments to stop this happening.
The researchers found that in the presence of a signal from TGF-beta, single cells broke away from the main tumour and spread via the blood to other tissues and organs, including the lungs. But the absence of a TGF-beta signal prevented single cells breaking away. Instead the tumour spread via clumps of cells in the lymphatic system which could only spread locally and could not spread to the blood or lungs.
Lead author Dr Erik Sahai, head of the Tumour Cell Biology Laboratory at Cancer Research UK’s London Research Institute said: “We have used cutting-edge filming techniques to study the behaviour of cancer cells. The results helped us to find the set of genes that are behind the spread of breast cancer – and that the genes need to be first turned on and then off in order for single cancer cells to be able to ‘relocate’.
“Surprisingly little is known about the way cancer cells spread through the body because it is so incredibly difficult to study. In a medium-sized tumour there could be a billion cells – and only a small proportion might break away and spread. So it is like trying to find – and understand – a moving needle in a very big haystack.”
In the UK in 2006 more than 45,500 women were diagnosed with breast cancer – around 125 women a day. Breast cancer is the second most common cause of death from cancer in women after lung.
Pamina Brassey, 49, West London, said: “I was diagnosed with breast cancer in 2008 and had a mastectomy in my right breast to remove the tumour.
“My cancer was caught early and I was told there was a 90 per cent chance that the cancer would not return.
“I feel lucky because it can be more difficult to treat breast cancer once it has spread. I think it is fantastic news that researchers have found out how breast cancer cells can spread around the body because this will open the doors for research into new potential drugs to prevent this happening – and increase survival from advanced disease.
“I feel back to where I was physically before I was diagnosed – I’m back into rollerblading and feel fantastic. It would be great to hear that more women in the future could have the same wonderful news.”
Arlene Wilkie, director of research and policy, Breast Cancer Campaign said: “This groundbreaking research is a major step forward in understanding how breast cancer spreads to other parts of the body, the main cause of death from this disease.”
Dr Helen George, head of science information at Cancer Research UK, said: “This crucial research unravels for the first time how single breast cancer cells leave a tumour and start to move around the body – something that until now has not been fully understood. Sadly the majority of women who die from breast cancer do so because their disease has spread from the breast to other parts of the body.
“This research opens doors to enable scientists to find ways to block the spread of cancer – and improve survival.
“More women are surviving breast cancer than ever before thanks to earlier diagnosis and better treatment – and we hope research like this will play a crucial role in helping more people survive this disease in the future.”
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Silvia Giampieri et al. Localised and reversible TGFB signalling switches breast cancer cells from cohesive to single cell motility. Nature Cell Biology 2009