Gene Linked to Aggressive Ovarian Cancer

September 19, 2005 08:40:57 PM PST
Researchers have discovered that overproduction of a gene called Rsf-1 may play a crucial role in the development of ovarian cancer, and might explain why some forms of this cancer are more deadly than others.

Tian-Li Wang of Johns Hopkins University School of Medicine, the senior author of the study, and her colleagues analyzed tissues from seven ovarian cancer samples, using a technique called digital karyotyping to identify "sub-chromosomal alterations."

They found "genetic amplification" -- or overproduction of the Rsf-1 gene, located on chromosome 11 -- in 13.2 percent of the most aggressive forms of ovarian cancer but not in any of the low-grade ovarian cancers.

"The gene Rsf-1 replicates a lot on chromosome 11, and that is associated with a more aggressive cancer," said Wang, whose study appears in Sept. 27 issue of the Proceedings of the National Academy of Sciences. "It's more aggressive and patients have a worse outcome."

This is the first time this genetic alteration has been identified, and the discovery could one day lead to new treatment options, Wang said. "This gene is a 'candidate' oncogene," she said. "An oncogene is a gene that will trigger cell growth abnormally, so if you block this you can inhibit cancer cell growth."

Several other oncogenes, such as HER2/neu for breast cancer, have already been identified by other researchers.

The new finding, Wang said, may eventually lead to the development of a drug to block the activity of Rsf-1 and thus stop the cancerous cell growth.

Ovarian cancer is the seventh most common cancer affecting women (not including skin cancer), according to the American Cancer Society. About 22,000 new cases will be diagnosed this year in the United States, and more than 16,000 women will die from the disease this year, according to society projections.

Ovarian cancer often has no symptoms in its early stages, so women are often diagnosed after the disease has progressed to a tough-to-treat stage. Experts have long been searching for an effective method to catch the disease in its early, more curable stages.

David C. Ward, deputy director of the Nevada Cancer Institute in Las Vegas, called the new study "well done," and added, "They have identified another gene which unfortunately has been amplified and has an adverse effect."

Eventually, pharmaceutical companies could "design compounds to target the amplification," said Dr. Yupo Ma, chief of hematopathology at the Nevada Cancer Institute.

Said Ward: "This is [like] one of the therapies we have for breast cancer. [The gene] Her2/neu is amplified and now there is an antibody against that, herceptin."

More information

To learn more about ovarian cancer, visit the American Cancer Society.

Scientists Spot New Breast Cancer Treatment Target

September 19, 2005 08:40:57 PM PST

This pathway was identified in research with mice and substantiated in laboratory tests of human breast cancer samples. The findings appear in the September issue of the journal Cancer Cell.

The researchers found that, in mice, recurrent mammary tumors displayed characteristics of cellular changes previously linked with breast cancer. The tumors also had increased levels of a transcriptional repressor -- a gene that affects the activity of other genes -- called Snail.

Levels of Snail were sufficient to induce the cellular changes in primary breast cancer cells and to promote mammary tumor recurrence in mice, the study found. When they screened human breast cancer samples, the researchers found that high levels of Snail expression also strongly predicted relapse in breast cancer patients.

"While it is not possible to confirm a causal role for Snail in human breast cancer recurrence until drugs are available to inhibit this pathway, we believe that treatment of patients with pharmacologic agents that block Snail expression or function may be a promising approach to preventing breast cancer relapse," study leader Dr. Lewis A. Chodosh, of the University of Pennsylvania School of Medicine, said in a prepared statement.

"Snail may thereby represent an important target for a new generation of cancer therapeutics directed against specific molecules involved in breast cancer recurrence," Chodosh added.

More information

The American Cancer Society has more about breast cancer.