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Designing Cancer-Killers: A Giant Leap Forward in Cancer Treatment?

In what could be one of the biggest breakthroughs in cancer treatment, researchers from the National Cancer Institute have been able to genetically change a patient's cells to battle cancer cells.

This treatment is one that researchers have been working on for years. But, in a study published in the journal Science, researchers have documented that their genetically-engineered cells have cured two patients of a deadly form of skin cancer, melanoma, which had spread throughout their bodies.

The hope is that this treatment proves to be helpful in treating a vast array of cancers.

"These results represent the first time gene therapy has been used successfully to treat cancer," said Dr. Elias A. Zerhouni, director of the National Institutes of Health in a press release. "Moreover, we hope it will be applicable not only to melanoma, but also for a broad range of common cancers."

Previous research has found that in some patients with melanoma, there are a few white-blood cells that are especially aggressive in fighting off cancer cells. The problem is, they do not exist in high enough amounts to ever significantly slow the rapid growth of a tumor. So, researchers tried to isolate those few aggressive cells from a patient, multiply them in a lab and then replace them into the patient's body.

The treatment, when used, worked. But in most cases, a patient does not contain any of these cancer-killing cells, so this treatment is not an option.

Therefore, researchers from the National Cancer Institute built off of this work and tried to take a patient's normal white-blood cells and turn them into melanoma-fighting cells.

The key to making a cancer-killing cell, it seems, lies in the genetic sequence of the cell itself. So, the researchers, led by Dr. Steven A. Rosenberg, used viruses to "infect" and deliver a new set of genes to healthy white-blood cells taken from each patient. When these cells are reinserted into the patient's body, they begin to make a specialized protein that hones in on cancer cells and destroys them.

In the study, the researchers injected these genetically-engineered cells into 17 patients with melanoma. While 15 of the men did not see any improvement in their condition, two of the men had such a positive response, that they have been disease free for almost two years since the start of the treatment.

The researchers caution that the long-term success of this treatment is yet unknown, and more work needs to be done to improve the strength to these cells so they can help more people with melanoma. However, the researchers remain cautiously optimistic that this technique can be successful and applied to various cancers.

"These very exciting successes in treating advanced melanoma bring hope that this type of gene therapy could be used in many types of common cancers and could be achievable in the near future," said Dr. John E. Niederhuber, acting director of the National Cancer Institute.

The team has even begun to develop other aggressive white blood cells in an attempt to treat other caners. "We have now expressed other [cells] that recognize breast, lung and other cancers," said Rosenberg.