Cancer researchers confer on disease-fighting strategies

Promising findings for combating certain cancers included the benefits of sunshine, multiple glasses of milk and many cups of tea.

By Susan J. Landers, amednews staff. May 1, 2006.

Washington -- Cancer research buzzwords reflect the areas that offer the best hopes for reducing cancer mortality and fending off this dread disease -- molecular-based diagnostics, DNA markers, gene expression, and even flavonoids and antioxidants.

That's why these topics were among the studies in the spotlight at last month's annual meeting of the American Assn. for Cancer Research in Washington, D.C.

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The future will bring changes in the diagnosis of cancer, said Angelo M. DeMarzo, MD, PhD, associate professor of pathology, oncology and urology at Johns Hopkins University School of Medicine in Baltimore. And many presenters indicated that molecular messages will provide important clues.

Avrum Spira, MD, assistant professor of medicine at Boston University School of Medicine, is exploring an approach for detecting lung cancer that combines results from a traditional bronchoscopy with gene expression profiles.

"We are not instituting a new test," Dr. Spira said. The high-risk patients in his study were suspected of having cancer and were already undergoing a bronchoscopy. The researchers took the additional step of gathering samples of normal-appearing epithelial cells of the upper airways to serve as diagnostic biomarkers. "Together, the two tests have a very high sensitivity for lung cancer."

Any improvement in lung cancer diagnosis could be important, he noted. The five-year survival rate for people diagnosed with stage IV lung cancer is only 5% but with earlier detection, while the cancer is still in stage I, five-year survival exceeds 60%.

In additional findings, researchers from Norway identified a set of 58 genes circulating in women's peripheral blood cells that seemed to signal the presence of breast cancer. "Early detection of breast cancer is the key to optimizing the success of treatment and patient survival," said Dr. Anne-Lise Borresen-Dale, professor and head of the genetics department at the Norwegian Radium Hospital's Institute for Cancer Research in Oslo.
Researchers from Epigenomics Inc., a molecular diagnostics company based in Berlin, with offices in Seattle, Wash., reported that free-floating DNA gleaned from blood is a key to early detection of colorectal cancer. "The test is already better than existing, noninvasive early-detection methods such as fecal occult blood testing," reported Catherine E. Lofton-Day, PhD, vice president for molecular biology and diagnostics at the company.

The researchers found that the presence of the methylated form of DNA encoding the so-called Septin 9 gene, which is involved in cell division, is found in plasma of up to 57% of patients with all stages of colorectal cancer, Dr. Lofton-Day reported.

Diet and lifestyle

Researchers also explored the roles that vitamin D and flavonoids, natural antioxidants found in plants, could play in the treatment and prevention of breast and ovarian cancers.

One new study supported a premise that vitamin D plays a significant role in reducing breast cancer risk. Researchers at Mount Sinai Hospital in Toronto found the reduction was most apparent among women exposed to the highest levels of vitamin D when they were between ages 10 and 19.

High exposure included working at an outdoor job, taking cod liver oil and drinking at least nine glasses of milk every week, said Julie Knight, PhD, a scientist at the hospital's division of epidemiology and biostatistics.

A second study of vitamin D indicated that consumption of 1,000 international units of vitamin D, particularly vitamin D3, or cholecalciferol, every day from supplements or fortified foods can provide protection from breast cancer. Average-per-person consumption of vitamin D is only about 320 IUs per day in this country, said Cedric Garland, PhD, professor of family and preventive medicine at the University of California, San Diego School of Medicine. The National Academies have set an upper safety limit of 2,400 IUs per day, he said.
An epidemiologic study of flavonoids determined that the plant-based antioxidants were associated with a reduced risk of breast cancer among postmenopausal women. Researchers from the University of North Carolina, Chapel Hill, and others, evaluated data from a large study of breast cancer incidence and risk factors among women living during the mid-1990s on Long Island, N.Y.
A second study found evidence that increased consumption of flavonoid-containing foods was linked to a reduced risk for ovarian cancer. Researchers from the Harvard School of Public Health looked at food intake surveys and ovarian cancer data from 66,000 participants in the Harvard Nurses' Health Study. They also analyzed individual flavonoids to evaluate their impact on ovarian cancer. The researchers found that nurses who consumed the highest amounts of the flavonoid kaempferol, which is obtained from caffeinated tea, broccoli and kale, had a 38% decrease in ovarian cancer.

Lead researcher Margaret Gates, a doctoral candidate at Harvard, cautioned that the findings still need to be confirmed before any public health recommendations can be made.