By FIONA MACRAE

Last updated at 11:30 10 January 2008

British scientists have unlocked one of the secrets behind how cancer spreads around the body.

The breakthrough, carried out at Manchester University, could help pave the way for a generation of drugs that would halt up to 90 per cent of cancers in their tracks.

Such drugs could be particularly effective against breast and lung tumours - two of the biggest killers.

More than 150,000 Britons a year are killed by cancer, and breast and lung tumours account for almost a third of those deaths.

The disease spreads when cancerous cells break away from the original tumour and are distributed around the body by the bloodstream.

Further tumours develop where these cells eventually end up and start multiplying.

Researcher Dr Chris Ward said: "Understanding how cancer cells spread is tremendously important for cancer research.

"It is the ability of tumours to invade other tissues and spread around the body that makes them so dangerous.

"The cancer just overwhelms the body."

Dr Ward used embryonic stem cells to study the mechanism cancer cells use to spread around the body.

He showed that a protein called Ecadherin is essential to keeping cells stuck together.

When levels of E-cadherin fall, other proteins move to the surface of the cells and they are able to break away and spread.

Researchers now aim to create drugs that interfere with this process.

Dr Ward said: "Potentially, our findings can be applied to the most common form of cancer, carcinoma, found in the breast, lung and gut for example, which makes up 80 to 90 per cent of all cancers."

Norman Barrett of the Association for International Cancer Research, which funded the study, said: "Dr Ward and his team are pursuing research which could change the lives of tens of thousands of people in the UK and many more across the world."

E-cadherin is one of several elements involved in cancer spread - known as metastasis - to have been identified in recent months.

Research at the Memorial Sloan-Kettering Cancer Center in New York appeared to suggest that loss of three short pieces of genetic material aids the spread of breast cancer to the lungs and bone.

The researchers, whose work is reported in the journal Nature, said: "These findings may enhance our ability to come up with more effective drugs."

Dr Mark Matfield, scientific coordinator at the AICR, such studies identified potential targets for new drugs.

"We are in a golden age of cancer research," he said.

"By no means all of these targets will develop into useful drugs but if only a proportion of them do, there is still going to be a lot more new treatments for cancer."