A combination of gold and green tea compounds may be the future of prostate cancer treatments, according to a new mouse study published in the Proceedings of the National Academy of Sciences.

Researchers from the University of Missouri found that a combination of a compound found in green tea leaves radioactive gold nanoparticles were able to destroy the tumor cells. The tea compound, which was attracted to the cancerous cells, helped to deliver the gold nanoparticles, which killed the cancer cells.

Researchers said large doses of chemotherapy, which sometimes have toxic side effects, are currently used to treat a variety of cancers, but the new treatment would require doses that are "thousands of times" lower than that of chemotherapy. The particles are small enough to destroy the diseased cells, but leave the healthy surrounding tissue and cells intact.

"By combining a natural component in green tea that has an affinity for prostate tumor cells, we have formed gold nanoparticles that have a high uptake in tumor cells," said Dr. Cathy Cutler, research professor at the MU Research Reactor and co-author of the study. "This formulation of gold nanoparticles, which has shown such tumor cell death at such a low dose in a model of aggressive human prostate cancer indicates it could be effective for aggressive prostate cancer."

The green tea compound used in the study, known as epigallocatechin-gallate, or EGCg, is an antioxidant that has been shown in prior research to have cancer-fighting properties.

According to the Centers Disease Control and Prevention, more than 200,000 men in the United States were diagnosed with prostate cancer, and more than 28,000 died of the disease in 2008.

There is currently no treatment for aggressive prostate cancer, which is the second leading cause of cancer deaths in men. In less aggressive forms of the disease, physicians inject hundreds of radioactive "seeds" into the prostate to treat the cancer, but the seeds have limited tissue penetration, so it is a treatment best used for early stages of the cancer that is contained in the prostate.

Dr. David Crawford, professor of surgery and radiation oncology at the University of Colorado Health Sciences Center, said the use of nanoparticles for a number of areas in medicine to deliver therapy is "exciting," and, while early in development, still promising.

But Dr. Derek Raghavan, president of Levine Cancer Institute at Carolinas HealthCare System, called the study "headline hunting" and noted the gap between data and clinical application is "vast." He said there are years of research needed to ensure the safety and efficacy of the treatment.

"I wish people working in basic labs would stop making these types of promises at such an early stage," Raghavan said. "They secure brief fame, but it is so disruptive to patients who are fighting for their lives. It also adds confusion when real progress is actually being made."

Lab animal data only occasionally easily translates into clinical application, but many studies based in animals make lofty promises without much follow-up, Raghavan said.

Nevertheless, the University of Missouri scientists were optimistic in their findings, and said they plan on following up their research in dogs, which they said get a form of the disease very similar to the human form.