Key finding brings vaccine to kill cancer a step closer

Scientists claim to have discovered way of harnessing body`s immune system to attack tumours.

Updated: Nov 05, 2010, 15:23 PM IST

London: British scientists claim to have discovered a new way of harnessing the body`s immune system to attack tumours, a breakthrough which they say could lead to the development of a new vaccine to treat cancer.

Using a mouse model, researchers at Cambridge University found a protein known as FAP (fibroblast activation protein alpha) which stops the body`s immune system from destroying cells that have become cancerous.

FAP is found in stromal cells -- a kind of tissue cell that usually races to the scene of a wound to aid healing. By turning off this process, they believe that the body would
cure itself of the disease.

In the past attempts to harness the immune system have failed because a protein appears to shield -- and even nurture -- cancer cells.

But destroying this molecule leaves the cancer completely defenceless and it is killed by the immune system, said the researchers.

Professor Douglas Fearon, the immunologist who led the study, said it was an "important step" that could radically change cancer treatments.

"I am excited by the research," he was quoted as saying by the Telegraph.

"It is possible we have found a very big piece of the jigsaw. The research is at an early stage but it is not too far-fetched to suppose that what has been seen in mouse tumours will also be found in human versions of the disease."

For their study, the researchers gentically modified mice so that they could turn off FAP production at will. They then gave the mice lung cancer and found that when FAP was
stopped the lung tumour cells were destroyed and the cancer began to rapidly "die".
They now plan to see what effects depleting FAP has on human cancers.

Previous vaccines created to prompt the immune system to attack cancerous cells have activated an immune response but inexplicably have almost never affected the growth of tumours.

Immunologists have suspected the activity of immune cells within tumours is somehow suppressed, but they have so far been unable to fully reverse it.

Prof Fearon said: "Further studying how these cells exert their effects may contribute to improved immunological therapies by allowing us to remove a barrier that the cancer
has constructed."

The new research sheds light on why the body does not destroy cancer cells like it destroys other illnesses. The protein FAP is found in connection to many cancers, including breast, bowel and lung tumours, the researchers said.
Prof Fearon: "These studies are in the mouse, and although there is much overlap between the mouse and human immune systems, we will not know the relevance of these
findings in humans until we are able to interrupt the function of the tumour stromal cells expressing FAP in patients with cancer."

The vaccine would not be administered as a prevention in advance but only when cancer is identified in a patient, he said.

PTI