Finding to Aid Ovarian Cancer Diagnosis

A Viennese research team has found that the expression of two specific genes is almost completely down-regulated in ovarian cancer tumors, which should aid the early diagnosis of the disease.

The symptoms of ovarian cancer seldom appear until it has reached an advanced stage, by which time treatment is not effective. A diagnostic for the early stage of the disease could save many, many lives. When researchers at the Medical University of Vienna (Austria) compared normal ovarian cells with advanced ovarian cancer cells, they found molecular genetic differences. The genes they identified as N33 and EFA6R are in some cases almost completely inactivated in the cancer cells.

"At present, it looks as though the two genes have already lost their activity before the appearance of clinical symptoms,” said Prof. Michael Krainer of the Clinic for Internal Medicine I at the University of Vienna. "We presume that this happens because methyl groups are attached to the gene's building blocks. This is a common means of regulating gene activity. Methylation like this is easy to detect and could be an early warning sign for developing cancer.”

The expression of several genes on a particular band of the human chromosome 8 in tumor cells from over 90 patients was measured during the project. In ovarian cancer, there is often a loss of this chromosomal band. Prof. Krainer's team had previously identified 22 genes. The current project has now been able to demonstrate that a total of five of these genes show very low expression levels in tumor cells. N33 and EFA6R stood out, as the reduction in their expression was associated with progression of the disease. The function of the genes is not known. N33 may be involved in the regulation of cell death and EFA6R in signal transmission, the scientists said.

"The next step in early detection is the diagnosis of molecular genetic markers such as methylations, as they provide information on the actual development of cancer in individual patients,” added Prof. Krainer. "This means that analysis of molecular genetic markers is an ideal match for diagnosis of genetic predisposition to breast and colon cancers, for example.”






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