Pitt researchers identify markers that could test for ovarian cancer
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A distinctive pattern of proteins in a drop of blood could provide the basis for a much-needed screening tool to detect early stage ovarian cancer.
Anna E. Lokshin and her colleagues at the University of Pittsburgh School of Medicine have identified a panel of biomarkers that indicate if the cancer is present.
Typically, "there are no symptoms or the symptoms are very vague," Dr. Lokshin said. "That's why 80 percent of ovarian cancers are diagnosed in stages 3 or 4, when it's too late to do something."
The experimental biomarker panel correctly distinguished between blood samples taken from women known to have early stage ovarian cancer and those from healthy women more than 96 percent of the time, she said.
The findings were presented last week in Washington, D.C. at the annual meeting of the American Association for Cancer Research.
Scientists had hoped that a protein called CA-125 would be a good marker for ovarian cancer, but studies have shown that it may be elevated in benign diseases, as well, Dr. Lokshin said. Also, only 14 percent of women with early stage disease have a high CA-125, Dr. Lokshin said.
Up to 95 percent of stage 1 ovarian cancers are curable, she said. Only 1 out of 5 women with advanced disease are alive five years after diagnosis.
The Pitt researchers examined whether multiple biomarkers could provide a sufficiently sensitive and specific way to identify the cancer early. To do so, they used technology that allows analysis of a hundred proteins in a drop of blood.
They began by identifying about 80 proteins associated with ovarian cancer. Then, using results from the protein analyzer, a sophisticated computer algorithm picked 17 to 20 markers that in combination could reveal the presence or absence of cancer, Dr. Lokshin explained. The researchers are still fine-tuning the selection.
She was recently awarded a grant to continue the research. In the next step, the biomarker panel will be used to test stored blood samples that were obtained annually from 80,000 women during a national trial.
"So, 120 of these women got ovarian cancer, and you've got a trail of blood drawn for up to 10 years prior to diagnosis," Dr. Lokshin said. With that, the researchers can see if the panel works, and how early it was able to pick up the developing cancer.
If that project is successful, then the panel might be ready for testing ina clinical trial.
It might be possible to develop a panel that can detect precancerous ovarian lesions, or to track response to therapy, Dr. Lokshin noted. Similar methods might also be used to screen for other kinds of cancer.
First Published April 5, 2006 12:00 am