Many people with cancer die not from their original tumour, but from secondary tumours that grow elsewhere around the body. Now we鈥檙e a step closer to understanding how cancers are able to spread.
of the Medical Research Council Cancer Unit at the University of Cambridge and his colleagues have been studying kidney cancer cells. They found that to spread, these cells tap into the same genetic 鈥渢ravel鈥� machinery normally used by healthy white blood cells to roam around the body.
They discovered this by comparing how active different genes were in the cells of four types of human kidney cancer 鈥� two of which were capable of spreading. They found that those that could spread had increased activity in two regions of the genome that act as accelerator pedals, amplifying the activity of nearby genes.
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These 鈥渆nhancers鈥� lead to increased activity of a gene called CXCR4, which is known to help white blood cells move around the body and into other organs to fight infections or disease. The gene was 10 to 20 times more active in the kidney cancer cells that could spread than in those that couldn鈥檛.
Turn it off
When the team studied databases of human and mouse gene activity, they found that the same two enhancers are normally only active in healthy white blood cells. The team found that silencing these enhancers in kidney cancer cells stopped them from being able to spread when they were injected into mice. When they reactivated the silencers, they began to move around the body again.
鈥淭hey are changing identity,鈥� says Vanharanta. 鈥淚t鈥檚 not that they鈥檝e become something else completely, but that they鈥檝e stolen a collection of different tricks from other types of cells.鈥�
Vanharanta believes that other cancers may also spread by stealing other cells鈥� tricks, and has some evidence this happens with breast cancer too. Ultimately, he says, it might be possible to stop cancers spreading by targeting these enhancers, but more work is needed first, he says.
鈥淭he mechanisms used by cancer cells to spread through the body are still poorly understood,鈥澛爏ays Marco Gerlinger of the UK Institute of Cancer Research. 鈥淭hese new insights could lead to new ways to predict whether a cancer is dangerous and likely to spread.鈥�
Cancer Discovery
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