Study sheds light on cancer spread
An international team of scientists have shown that tumours use a protein called lysyl oxidase (LOX) to help prepare other parts of the body for invasion.
The process by which cancer spreads is known as metastasis and involves the migration of cancer cells from the initial tumour to remote areas of the body.
Scientists believe that nine out of ten cancer deaths are due to cancer spreading to other parts of the body.
Researchers at Stanford University School of Medicine have shown that, rather than being a passive and random process, cancer cells send molecules ahead to overcome the body's natural defences and prepare the so-called 'pre-metastatic niche' for colonisation.
Senior author Dr Amato Giaccia, professor of radiation oncology at Stanford, revealed: "Metastasis is not a passive process. Cells don't just break off the primary tumour and lodge someplace else.
"Instead the cells actually secrete substances to precondition target tissue and make it more amenable to subsequent invasion."
In order to investigate how rogue cancer cells put down roots and form secondary tumours, the researchers carried out a series of studies in mice.
They focused on the LOX protein, which usually helps to strengthen connective tissue, but has previously been shown to be involved in metastasis.
Publishing their findings in the journal Cancer Cell, they reveal that by blocking the production of LOX in mice, they were able to reduce the rate of cancer spread.
Inhibiting the production of LOX also prevented bone-marrow-derived cells - which are required for the formation of pre-metastatic niches - from flocking to the site.
When LOX production was re-established, specialised white blood cells accumulated in the mice's lungs and secreted a protein that breaks down collagen and allowed cancer cells to enter.
The researchers hope that, by blocking this cascade of events, it may one day be possible to block the migration of cancer cells and prevent metastatic cancer.
"We've never really understood before how normal tissues are modified to allow metastases to target and successfully invade them," said Dr Giaccia.
"Now we know that LOX goes to the target tissue and attracts CD11b and other bone-derived cells to the pre-metastatic niche.
"If the mouse data is transferable to humans, and we have reasons to think it will be, we really believe we may have found an effective way to treat human disease."
Dr Julie Sharp, Cancer Research UK's science information manager, said: "A better understanding of how cancer spreads is crucial to improving the treatment of the disease.
"This research takes scientists a step closer to understanding this major problem - the next stage will be to find out if the LOX protein can be switched off to stop cancer spreading."
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