Gene screen shows wider picture of blood cancer

Scientists on Wednesday published the broadest picture yet of the likely genetic causes of multiple myeloma, a common form of blood cancer in which malignant white blood cells proliferate unchecked.

The map comes courtesy of a trawl through the DNA of 38 people with the disease, according to the research carried out by 21 institutions in North America.

White blood cells develop in the bone marrow and make antibodies that help the immune system fight microbes. Multiple myeloma cripples these defences, leaving victims dangerously exposed to infections.

The survival rate is poor compared to other cancers. About 20,000 new cases are diagnosed in the United States each year, and fewer than 40 percent survive to five years.

Genomic sequencing entails looking through the DNA code for tiny variations that could explain why some people are at risk of disease while others are not.

The cost of sequencing has fallen sharply in recent years, which means researchers are able to cast their net wider than before. Previous studies into multiple myeloma have been able to look only at the DNA of a single patient.

"For the first time we are able to see on a molecular basis what might be causing this malignancy," said David Siegel of the John Theurer Cancer Center at Hackensack University, New Jersey.

"We already know what causes many types of cancer, but until now we had few clues to the causes of myeloma."

A preliminary analysis of the DNA variations suggests there are common pathways, especially in the cellular protein-making machine, that enable a malignant cell to survive, invade and spread.

The initial benefit from this is understanding more about the basics of multiple myeloma.

Eventually, doctors hope, it will lead to drugs to block the disease.

"It's going to take a lot of biological research to sort out whether these will make good drug targets," said Todd Golub, director of the cancer programme at the Broad Institute of Harvard University and the Massachusetts Institute of Technology (MIT).

"But this is an example of how genetic analysis can help point the field in the right direction very dramatically."

The study appears in Nature, the British science journal.

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