A genetically engineered strain of bacteria wipes out the insides of tumors and could be useful as cancer therapy.

The idea of using bacteria against tumors goes back to the 1940s. The researchers didn't get too far, either because the bacteria they used weren't very effective, or they were too toxic.

The researchers thought this idea was worth revisiting now -- with their ability to genetically engineer organisms -- to see if they could engineer a strain with suitable properties.

The research team reports screening 26 different types of bacteria that grow only in oxygen-free, or anaerobic, conditions, similar to the environment found in the middle of a tumor.

Two of the 26 strains appeared particularly promising, according to the researchers, because they homed in on the tumor, even though they were injected intravenously rather than directly into the tumors.

The two strains also spread throughout the tumor, destroying live tumor cells adjacent to the dead regions in the very center of the tumor. Most the organisms they tested formed a nest in the middle rather than spreading throughout.

But although both strains killed the tumor cells, they also killed the mice 6 hours later. So the researchers took one of the two strains, called C. novyl, and modified it so that it did not produce the toxin that ended up killing the mice. The bacteria still had the same effect on the tumor cells, however.

When the spores were administered with chemotherapy, extensive death of tumor tissue often occurred within 24 hours, resulting in significant and prolonged antitumor effects.

This strategy, called combination bacteriolytic therapy (COBALT), has the potential to add a new dimension to the treatment of cancer. They basically turn the tumors into jelly.

Proceedings of the National Academy of Sciences Early Edition November 27, 2001;10.1073

Dr. Mercola's Comments:

In contrast to genetically engineering our food supply, this approach seems a far more rational use of the technology. I still favor a more proactive approach which would prevent the cancer to begin with, but it seems clear that effective cancer therapies will ultimately need to employ some biological intervention to decrease the toxicity of the treatments. The key is providing highly targeted agents so the total toxic burden can be decreased. We have seen a real life analogy of how effective this can be in the last two months in Afghanistan. The U.S. military has shown the world how technology built around weapons operating at extremely long ranges, hitting targets with unprecedented precision, and relying as never before on gigabytes of targeting information gathered on the ground, in the air, and from space. A constellation of information-gathering systems -- from imaging satellites to surveillance aircraft to ground troops -- combined to enable US forces to precisely find and hit the al Qaeda terrorist network and its allies in the Taliban while minimizing civilian deaths relative to what they would have been without the precision, and opening the way for proxy forces to advance on the ground. Only about 10 percent of the bombs dropped in the Gulf War were precision-guided, meaning they could either sense and hit a target dot from a laser beam, or could pick up signals from a global positioning system (GPS) satellite. By contrast, 90 percent of the bombs dropped in Afghanistan have been precision munitions. In biological terms the equivalent precision will be gained from immunological aided agents -- most likely by individualized antibodies against the specific cancers that are facilitated by advancements in biotechnology. <