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Cells given lessons in how to fight cancer
26 October 2002
From New Scientist Print Edition.
Nicola Dixon
Clare Wilson

Enlarge Fighting leukaemia

People with leukaemia could in future be spared repeated courses of debilitating chemotherapy and have a far higher chance of a complete cure.

A new therapy is being tested that relies on inducing the body's own immune cells to home in on cancer cells. And the approach, announced last week by a team at the University of California in San Diego (UCSD), should be suitable for all types of leukaemia, unlike many other kinds of experimental immunotherapy that only work against subsets of cancers with particular cell surface proteins.

The researchers grew patients' leukaemia cells side by side with their immune cells, in a cocktail of growth factors. The result was a batch of immune cells primed to kill the same cancer cells they had been incubated with, whatever type that was. The immune cells worked well against cancer cells in the lab, and the researchers are now planning future patient trials.

Leukaemia is caused by white blood cells turning cancerous and dividing uncontrollably. Treatment is usually a gruelling course of chemotherapy to kill the cells, often followed by a bone marrow transplant. But if just a few cancerous cells survive they start dividing again - patients relapse, and have to have more rounds of chemotherapy. Four-fifths of adult leukaemia patients die within five years.

The UCSD team say their new approach could seek out and destroy any cancer cells that survive the first course of chemotherapy, banishing the leukaemia once and for all.

To test their idea, they took blood from 12 patients with acute myeloid leukaemia, the most common form in adults. They extracted the leukaemia cells and immune cells called T cells, and grew them together with different growth factors for six weeks.

First they added factors that turned the leukaemia cells into "antigen-presenting cells", which specialise in stimulating an immune response against their surface molecules (normally pinched from viruses). Then they added growth factors that primed the T cells to do their job, of recognising the antigen-presenting cells' surface proteins as foreign. Lastly they added factors that made the T cells multiply into a formidable army of cancer-killing cells.

Edward Ball, head of blood and bone marrow transplantation at UCSD, says the strategy should work for any type of leukaemia you can coax into becoming antigen-presenting cells. "It doesn't matter what surface molecules the cancer cells have," he says. "If the molecules get presented to the T cells, they should activate the cells against that kind of cancer."

Mark Dudley, a researcher in immunotherapy at the National Cancer Institute in Bethesda, Maryland, says one of the biggest problems in this field is targeting the right cancer surface molecules. He says: "This sounds a good way to do it."

From issue 2366 of New Scientist magazine, 26 October 2002, page 24

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