How cancer grows and spreads - Spreading around the body
One of the things that makes cancer so difficult to treat is the fact that it can spread around the body. Cancer cells break away from the original primary tumour and spread through the bloodstream or the lymphatic system, forming new secondary tumours in organs such as the lungs, liver or brain. Scientists call this process metastasis.
Over the years, Cancer Research UK scientists have uncovered many of the mysteries of how cancer cells spread, and we continue to fund pioneering research in this vital area today.
Here's a short movie from Dr Erik Sahai's lab at our London Research Institute, showing breast cancer cells spreading. You can see the cells (small green blobs) moving from the top left towards the centre of the image. This was taken down a high-powered microscope - the cells have been labelled with a green fluorescent 'tag', and the film has been sped up.
At the London Research Institute, Dr Erik Sahai is using sophisticated imaging techniques to study how cancer cells move. He recently discovered two important molecules that work together to control cancer spread.
Here is a short movie from his lab showing the three-dimensional shape of a breast cancer cell - the 'spikes' around the outside of the cell act like little 'legs', helping it to move through the body.
Also at the London Research Institute, Dr Nancy Hogg is studying how white blood cells move around the body to fight infection. These 'defence' cells travel in the blood and squeeze out into the tissues where they’re needed.
There are many parallels between the way in which white blood cells do this and how cancer cells spread around the body. So understanding more about how white blood cells move will shed more light on the mechanics of metastasis.
Most of the cells in our bodies stick to their neighbours through the help of 'Velcro-like' molecules on their surface known as integrins. Integrins are vital for forming structured tissues and organs, like the skin and the lungs. But they also help cancer cells that have broken away from a tumour to take root elsewhere in the body.
Professor Ian Hart at Barts and The London School of Medicine and Dentistry has discovered that a particular integrin is found in some aggressive cancers that have a poor outlook. His work could lead to ways to detect cancer once it has spread and, one day, even help to prevent the process in the first place.
In Edinburgh, Professor Maggie Frame is using cutting-edge imaging techniques to watch the effect of drugs that block two key proteins involved in cancer spread, to see if the drugs can keep cancer cells at bay.
In1889, London doctor Stephen Paget asked “What is it that decides what organs shall suffer a case of disseminated cancer?” - why do some types of cancers seem to spread only to specific parts of the body, while other types spread elsewhere.
This led to the ’seed and soil’ concept – spreading cancer cells are like seeds from rogue weeds, spreading around a garden. But they can only root and grow if they land in suitable soil – namely particular parts of the body that can support and maintain their growth.
At the University of Oxford, Professor Ruth Muschel found important new clues pointing to how cancer cells ‘seed’ in the brain, challenging the current view of how this happens. It was thought that cancer cells spread through nerve tissue, but Dr Muschel discovered that they actually grow along blood vessels. Her work could lead to new treatments for patients whose cancer has spread to the brain.
And Dr Janine Erler at The Institute of Cancer Research published pioneering research in 2009, showing that an important molecule called LOX ‘prepares the ground’ for cancer spread. The research is still at an early stage, but finding ways to block LOX could lead to future treatments to prevent the spread of cancer.
As well as funding groundbreaking lab research into metastasis, we are also supporting important clinical trials aiming to treat cancer that has spread. For example, we recently funded part of an international trial which showed that giving chemotherapy around the time of surgery improves the outlook for people whose bowel cancer has spread to their liver.
Research like this is essential if we are to find out more about how cancer spreads, and translate this knowledge into effective strategies to beat the disease. Finding the best ways to tackle cancer spread will save thousands more lives every year.



