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    California Pacific Currents 2001

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    Herbs as Radiosensitizers May Offer Hope in Treating Brain Tumors

    Garret Yount, PhD

    A diagnosis of glioblastoma multiforme is nothing less than devastating. This type of brain tumor grows exceedingly rapidly, sometimes doubling in size every 10 days, and is almost always fatal. The tumors are generally treated by surgery followed by radiation therapy. However, the usual time of survival for patients has remained about one year, regardless of therapeutic approach. Unlike other types of tumors, glioblastomas tend to be resistant to radiation.

    “We need to conduct more research on substances known as radiosensitizers, which increase glioblastoma cells' sensitivity to radiation,” says Garret Yount, PhD, a scientist and molecular biologist at the Research Institute. “Although some chemotherapeutic agents will sensitize brain tumors to radiation therapy, these agents are also toxic and can create other problems for patients. We need to investigate nontoxic substances that might serve as radiosensitizers. Traditional Chinese herbal medicine is a vast body of clinical knowledge untapped by Western science and could offer some hope in this area.”

    Late last year, Dr. Yount and his co-investigator, Yifang Qian, MD, PhD, were awarded a three-year grant from the National Institutes of Health (NIH) to determine if certain anticancer herbs can be effective radiosensitizers for patients with glioblastoma. The study is being conducted in the Research Institute laboratory, with the help of technician Jeremy West and two researchers in the Department of Radiation Oncology— Terrence Donlon, PhD, and Dan Glaubiger, MD.

    Blending Ancient Healing Principles with Modern Technology
    What's exciting to Dr. Yount about this research is the blend of traditional Chinese medicine, in the form of herbal compounds, with the latest technology, represented by a $60,000 DNA microarray machine (purchased with the NIH grant funds). “The DNA microarray technology, which is new in the last several years, enables us to measure the activity of hundreds of genes at a time using laser scanners and a computer. All that was previously possible was determining the activity of one gene at a time. This new technology allows us to cast a broad net when asking what kind of molecular pathways are involved,” explains Dr. Yount.

    To conduct the research, brain tumor cells are taken from patients during surgery. The tumor cells are kept alive in the laboratory, and an herbal liquid is applied to them in varying concentrations. Then the cells are radiated. The DNA microarray technology allows the researchers to look at patterns of gene expression at many stages during the process, revealing how the herbs work from a modern genetic perspective.

    “The reaction of the medical community to this research is very positive,” says Dr. Yount. “It's not a radical idea that plants have medicinal uses—that knowledge has been around for thousands of years. And applying state-of-the-art technology to study how herbs might sensitize brain tumors to radiation therapy brings herbs onto the same playing field as conventional pharmaceuticals.”

    Following a Research Path with Heart
    Dr. Yount chose this particular path of research for both professional and personal reasons. On a professional level, Dr. Yount did his post-doctoral work at the Brain Tumor Research Center at the University of California at San Francisco (UCSF). There he learned that a visiting scientist from China had done studies on brain tumors and herbal remedies in mice. The results were hopeful and were published in a Chinese medical journal not widely read by Western doctors.

    On a personal level, Dr. Yount's father was diagnosed with end-stage leukemia and told he had between six months and two years to live. That was 11 years ago. Upon diagnosis, he started using traditional Chinese medicine (herbs and qigong), in addition to standard chemotherapy. Alive today, he has beaten the statistics from a Western perspective. From an Eastern perspective, he is now “coexisting peacefully” with the cancer.

    Thus, Dr. Yount was determined to obtain NIH funding to prove the value of this ancient medicine. He feels especially fortunate to be working with Dr. Qian, a board certified psychiatrist from San Francisco General Hospital who was also trained in traditional Chinese medicine in Beijing. As a physician, Dr. Qian treats patients with modern psychiatric medications, and as a researcher, she identifies herbal compounds that are ideal candidates for further study.

    “You hear anecdotes about people with glioblastomas the size of tennis balls eating herbs and having good results after surgery and radiation therapy,” says Dr. Yount. “But anecdotes don't qualify as science. Running these herbs through the same tests that we apply to chemotherapies, for example, will show us whether there is a provable science behind these age-old remedies.”