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Week: 579.6 Part 2

Guest: Dr. Jerzy Jankun, Prof. Urology, Medical College of Ohio, Toledo 

Topic: Green tea vs. cancer 

Host/Producer: Steve Girard 

NEMA: Aaron will be a regular contributor to The Heart of the Matter. Up next, the herbal remedy that stands up to cancer.... 

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NEMA: It was an instance of something hiding in plain sight. Dr. Jerzy Jankun and his colleagues at the Medical College of Ohio were looking to synthesize a substance that would block the action of a certain enzyme essential for cancer tumor growth. The so called urokinase inhibitors they had on hand were not very effective, and in fact had a toxic result. What they found was a natural product that carried a special kind of inhibitor that was very effective, and safe. Dr. Jankun, what was the road that led to the study of the properties of green tea as a cancer fighter?  

JANKUN: For some time, we know that tumors...or cancer, are over expressing an enzyme that is called urokinase. And you can find these enzymes in a relatively high level in different tumors...like breast, colon, brain, kidney... so people thought that by inhibiting these enzymes, maybe we'd be able to do something good for the patient. And the idea was that this particular enzyme, which is a protolytic enzyme, is responsible for all the bad properties of the malignancy, like metastasis... meaning spreading out through the body...local invasion, ability to grow through the healthy tissue, and the process known as angiogenesis...formation of a new vessel around the tumor. And we and other people...maybe more important...other people and we, found out that inhibition of the urokinase is not only limiting angiogenesis, the local invasion and the metastasis, but more importantly, is reducing the rate of tumor growth. Unfortunately, most of the known inhibitors are toxic in inhibitory activity, or are very weak inhibitors of the urokinase. So we started to look for another inhibitor, with the hope that we will be able to find out something more potent. And we used a computerized database with almost, at this moment, 250 thousand different chemicals...and a specialized computer program which is looking for those inhibitors. And we found a couple hundred different compounds, including the polyphenols...which are a major ingredient of green tea. For a long time, we did not know about the connection with green tea, but it seems to be that the polyphenols are inhibiting the urokinase well.  

NEMA: Do you know why there's such a difference between the polyphenols of green tea versus other teas...I mean in the way it affects cancers?  

JANKUN: Green tea is fermented, and in the process of fermentation, black tea is produced. Unfortunately, again, during the process of the fermentation, most of the polyphenols are oxidized. All benefits of having good inhibitors of urokinase...during production of the black tea...are lost.  

NEMA: What is the next hurdle that has to be jumped to confirm your deductions about the anti-cancer benefits of green tea?  

JANKUN: ...we are trying to explain what happened, but we have to look from the mechanism point of view, and find out what really happens in an animal model. Also, we would like to continue this research, and look for more specific and more potent inhibitors. So, therefore, we are going to extend our search for even more different compounds...and we will try to produce some derivatives of compounds which we've already found, in hope that we will be able to produce more potent anti-cancer agents.  

NEMA: What I found interesting is that most urokinase inhibitors are toxic to the body at far lower doses than those found in normal green tea...but yet the tea and its form of polyphenols are not poisonous...  

JANKUN: I don't know...the best answer may be that God loves to create in this way. I don't know...only one explanation that I have is that EGCG came from the natural products, and it happens that it's not toxic. I have a great hope for this particular compound and some of its derivatives, which we will be able, hopefully, to produce.  

NEMA: There seems to be a reawakening of sorts to what were called home remedies...or perhaps cultural medicines, such as the green tea...which help the body get well or stay healthy.  

JANKUN: Oh yes, very much so. I was a firm unbeliever in home remedies and that kind of natural products medicine, garlic, soybeans, even green tea...and what converts me, it was really this discovery of EGCG. We had not been looking for this particular compound. It was given to us by a machine, which does not have any feeling...by a computer program which generated this program, this compound. So, when I saw it I said to myself, My goodness, it might be that we have an explanation why green tea really can inhibit growth of some tumors, and why green tea could prevent the formation of the tumors.  

NEMA: I know you have something to say to those people who may want to go out and get boxes of green tea...  

JANKUN: ...please consult your physician. He's your best friend, and he will be able to tell you if you can or cannot drink green tea. That is really based on the many phone calls we recently have received from very, very desperate people who are looking for some kind of miracle, and definitely, green tea does not belong to this category. it's a very interesting finding, it's a very promising finding. But it's not approved by FDA, it's not in a therapy yet, and it's not on a clinical study...so, be extremely careful.  

NEMA: Dr. Jerzy Jankun, professor of urology at the Medical College of Ohio. Thanks for joining us for today's program. If you have any comments or suggestions, contact this station. Or visit our home page at:


...for a look at transcripts of this or past programs, or to find out more about the National Emergency Medicine Association. I'm Steve Girard at The Heart of the Matter.

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