Researchers from the National Cancer Institute (NCI) say they have found a way to turn normal white blood cells into cancer fighters. What's more, their technique actually helped 2 patients overcome melanoma that had spread to distant parts of their bodies. If their method can be perfected, it holds promise for attacking other common types of cancer, they write in a paper published online today in Science Express.

Cancer researchers have been trying for decades to find a way to make the body's immune system recognize cancer cells and attack them, the same way it attacks viruses or transplanted organs. This approach is known as immunotherapy, and researchers sometimes speak of cancer "vaccines" when describing these types of treatments. White blood cells are part of the immune system.

The NCI researchers used gene therapy to make normal immune system cells deadly to metastatic melanoma, a particularly difficult form of cancer to treat.

In lab work, they also created altered immune cells that would attack other types of cancer cells, hinting at wider uses for this treatment.

"These results represent the first time gene therapy has been used successfully to treat cancer," said Elias Zerhouni, MD, director of the National Institutes of Health, of which NCI is a part. "Moreover, we hope it will be applicable not only to melanoma, but also for a broad range of common cancers, such as breast and lung cancer."

Though the results are exciting, they're not ready for widespread use yet, said Len Lichtenfeld, MD, deputy chief medical officer of the American Cancer Society.

"It is probably going to take several years of further investigation before we fully understand the impact of this approach, " he said.

Nevertheless, "We look forward to continued reports as this research enters its next phase in the treatment of patients with cancer," he added.