Jefferson scientists find zinc may help prevent esophageal, or...( Cancer researchers at Jefferson Medical...),Health

Oral and esophageal cancers are associated with nutritional zinc deficiency, and a rise in the expression of the enzyme COX-2 is connected with these cancers.

Louise Fong, Ph.D., assistant professor of microbiology and immunology at Jefferson Medical College of Thomas Jefferson University, and her co-workers have found that zinc given orally to zinc-deficient rats reverses the development of precancerous conditions in the esophagus and tongue and reverses the high expression of COX-2 there as well.

These findings suggest that zinc supplements may prevent the development of esophageal or oral cancers, particularly in developing countries where zinc deficiency is a problem. The researchers reported their findings January 5, 2005 in the Journal of the National Cancer Institute. Zinc in the diet comes mostly from red meat and seafood. Whereas up to 10 percent of Americans have a zinc-deficient diet, as many as 2 billion individuals in developing countries are zinc-deficient. Epidemiological evidence show the incidence of esophageal and oral cancers is rising in recent years. As many as 13,000 Americans die from esophageal cancer each year.

Dr. Fong has been studying zinc deficiency and its connection to esophageal cancer for some 20 years, and has developed animal models of zinc deficiency and cancer susceptibility. Zinc deficiency, she says, increases cell proliferation in the esophagus and in the tongue, making both areas susceptible to carcinogens and increasing the risk of cancer development. In 2002, Dr. Fong reported that rats given a carcinogen while on a zinc-deficient diet developed esophageal cancer. Giving zinc prevented the cancer.

Dr. Fong wanted to know if zinc could regulate COX-2 exp
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7-Jan-2005