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"Those who have no time for nutrition and exercise had better reserve a lot of time for disease." - Michael Colgan, Continuing Medical Education Lectures, 1988

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Many Foods Seem to Offer Some Cancer Protection

DAN VERGANO
© 1999 Medical Tribune News Service

2 September 1999

WASHINGTON D.C. - Researchers descended on the nation's capital to discuss foods that may reduce the risk of cancer.

At a news conference held to open the annual meeting of the American Institute for Cancer Research, scientists discussed the state of medical knowledge about the beneficial effects of so-called phytochemicals in foods like soy, tea and red wine.

``Our life and our well-being depend on understanding these foods,'' said Dr. Vay Liang W. Go of the University of California, Los Angeles Center for Human Nutrition, who predicted that ``early in the next century,'' physicians will prescribe certain foods to individuals to prevent cancer.

With increased understanding of how certain genes predispose some people toward certain cancers, Go argued, physicians will be able to fine-tune diets to contain phytochemicals that counteract defective genes.

``Physicians need to be educated in nutrition,'' said Dr. Richard Rivlin of Memorial Sloan-Kettering Cancer Center in New York. He complained that only one-quarter of doctors receive such training currently, often leaving patients more knowledgeable than their physicians about the cancer prevention benefits of foods.

``We've moved beyond simply telling people to eat fruits and vegetables,'' said Rivlin. Researchers have shown that the risk of prostate cancer drops for people who regularly eat tomato products, he noted. Other work has shown a decline in colon cancer among those who regularly eat soy products, drink tea and consume foods rich in selenium. In addition, research presented at the conference demonstrates how foods interact, such as augmentation of the blood-thinning effects of garlic when vitamin A is added to the diet, or a similar effect for vitamin E combined with zinc-rich foods.

Much of the interest in diets rich in phytochemicals reflects such foods' role in a diet that reduces obesity, said Dr. David Heber, a colleague of Go's. The AICR recommends people maintain a healthy weight to lower their cancer risk. Women with breast cancer are at a higher incidence of recurrence of the disease if they put on weight, noted Rivlin.

As many as 70 percent of all cancers spring from a poor diet and bad lifestyle choices like smoking, said Heber. ``It's developing now that cancer is not a genetic disease as has been thought, but one where genes make people susceptible to illness.'' A diet that features vegetables and fruits, and relegates meat as a side portion, can help prevent cancer, he asserted.

At the news conference, Heber discussed new medical understanding of lycopenes, the cancer-fighting compounds found in tomatoes and carrots.

Processing of these foods into sauces actually increases the amounts found in foods, said the physician. Because the food industry has started to add phytochemicals to foods, the medical community should reach out to the agricultural producers, he added, to ensure those enriched products receive healthy doses of genuinely healthy supplements in the future.

Among the food touted in AICR literature were beans and raspberries and cruciferous vegetables like broccoli. Sessions held Thursday at the meeting focused on the cancer fighting properties of tea, soybeans, garlic, grapes, and the trace mineral selenium.

Researchers Say Tumors Form Their Own Blood Vessels

PAUL CANDON
© 1999 Medical Tribune News Service


Cancer researchers have identified a previously unknown manner through which aggressive cancer cells form new blood vessels.

Scientists at the University of Iowa reported that some types of tumor cells can mold into channels and actually turn into blood vessels themselves. This finding could lead to new treatments for some types of cancer.

Previously, scientists have found that cancerous tumors attracted nearby blood vessels to nourish the growing cells; as a tumor grew, it would send signals for the growth of new blood vessels, a process called angiogenesis. This process has been the subject of a great deal of cancer research.

However, some aggressive cancers are not affected by conventional therapies or even experimental chemotherapies that affect angiogenesis in laboratory experiments and some less-aggressive human cancers.

Now, the Iowa researchers have discovered that as certain cancer cells become more deadly, they begin to form into primitive channels to form blood vessels. These channels form between tightly packed groups of tumor cells in a manner only seen in early embryos. The new blood vessels ultimately connect with pre-existing vessels at the edge of the tumor. This process is completely independent of angiogenesis and may explain why therapies that attack angiogenesis are ineffective in the treatment of some cancers.

The research team found this process in melanomas of the eye and skin, but has evidence that it occurs in other cancers as well.

The Iowa researchers also teamed up with scientists at the Human Genome Research Institute in Bethesda, Md., and identified genes responsible for this process.

``There are now specific genes that could serve as new therapeutic targets that are clearly associated with the aggressive tumor cells and not the non-aggressive ones,'' said the study's senior author, Mary Hendrix, deputy director of the University of Iowa Cancer Center and professor and head of anatomy and cell biology. ``Essentially these markers may predict which tumors are most likely to spread and which ones will not,'' she explained.

Hendrix said she feels the research ``will form the basis of new therapeutic strategies that could be developed to inhibit these aggressive tumor cells.''

However, when these findings will translate into a useful cancer therapy is unclear. ``We're very excited and we're optimistic about developing these observations,'' Hendrix commented, ``but at this time, we can't honestly predict when we would see them in the clinic.''

``It's an exciting finding. It's clearly important,'' said Christopher Widnell, scientific director in the research department of the American Cancer Society's national office in Atlanta. However, he cautioned that no one is sure yet whether this process occurs in many types of tumors or just the ones studied. ``At this point, one doesn't know how broad an occurrence this is,'' Widnell explained, ``but it certainly is one of great significance in the area of melanomas that seems to be absolutely unquestionable.''

The study is published in the September issue of the American Journal of Pathology.


PRIMARY SOURCE: American Journal of Pathology (1999;155; )

Copyright © Laurence D. Watkins (brain@brainsurgery.co.uk) except as stated in the Copyright and other notices

Last update: 03 October 2004