Roanoke Times
                 Copyright (c) 1995, Landmark Communications, Inc.

DATE: THURSDAY, May 20, 1993                   TAG: 9305200154
SECTION: NATIONAL/INTERNATIONAL                    PAGE: A-12   EDITION: METRO 
SOURCE: Associated Press
DATELINE: ORLANDO, FLA.                                LENGTH: Medium

FOOD-DERIVED MEDICINES STUDIED AS CANCER FIGHTERS

An emerging new field called chemoprevention is looking for ways to stop cancer by sidetracking the progression of cells from normal to malignant - a process that can take decades after exposure to a cancer-causing substance.

Experts long have noticed that people who eat lots of fruits and vegetables that are rich in vitamins and other nutrients have a lower risk of cancer. Now, they are trying to isolate the cancer-preventing chemicals in these foods to make medicines to keep people healthy.

Reports on several of these cancer-preventing strategies were presented Wednesday at a meeting of the American Association for Cancer Research.

"These are not ready to put on everyone's breakfast table yet," said Dr. Michael Sporn of the National Cancer Institute. "But this has gone from a dream and a fantasy to reality. It's very exciting."

While experts agree that food is usually the best way to get essential nutrients, highly concentrated supplements may be necessary to short-circuit cancer once damage occurs.

Dr. Ann Kennedy of the University of Pennsylvania recently began a study of a soybean derivative to prevent mouth cancer. The substance, called Bowman-Birk inhibitor, is being given to 24 people who have precancerous mouth growths.

The patients are taking about as much of this material as they would get from eating a quart of tofu daily. It appears to work by inhibiting a variety of enzymes known as proteases that play a role in transforming cells into cancer.

"We believe we are turning them back into normal cells," Kennedy said.

Dr. Michael N. Gould of the University of Wisconsin said he hopes to begin human studies soon to test the cancer-fighting powers of plant oils. Two of these - limonene, extracted from orange peels, and perillyl alcohol, found in tiny quantities in lavender oil - have been shown to work against breast cancer in lab animals.

In animal studies, he said, "we got both the prevention of cancer and the regression of cancer."

He cautioned against trying to stay healthy by consuming orange peel or lavender oil, however. The active ingredients are found in low levels in these products. Getting enough to be useful would mean eating vast amounts of orange peels or toxic quantities of lavender oil.

Perhaps the most advanced research into chemoprevention involves synthetic forms of vitamin A. Dr. Waun Ki Hong of M.D. Anderson Cancer Center in Houston has shown that Accutane, a kind of vitamin A sold as a prescription acne medicine, can reverse precancerous mouth growths like those being treated experimentally with the soy derivative.

Among other reports at the meeting:

Hong said his group is enrolling 1,000 patients in a study to see if Accutane can prevent the emergence of new cancers in people who have been successfully treated for mouth tumors.

Dr. Scott M. Lippman of M.D. Anderson is investigating whether a combination of Accutane, interferon and radiation therapy is effective against cervical cancer.