Biomarker may identify ovarian cancer
 

'Biomarker' may identify ovarian cancer
Guelph university scientists hope to detect early stages of 'silent killer'
<TABLE width="100%" border=0><TBODY><TR><TD> </TD></TR><TR><TD>Melissa Leong</TD></TR><TR><TD>National Post</TD></TR></TBODY></TABLE>

<TABLE style="FLOAT: right" cellSpacing=0 cellPadding=3 width=250 align=right border=0 valign="top"><TBODY><TR><TD><TABLE cellSpacing=0 cellPadding=2 border=0><TBODY><TR><TD>http://a123.g.akamai.net/f/123/12465...ood.jpg?size=l</TD></TR><TR><TD class=storycredit>CREDIT: Canwest News Service</TD></TR><TR><TD class=storycredit>Scientists at the University of Guelph are in the process of developing a way to test for ovarian cancer using the cancer's biomarkers found in the blood. Ovarian cancer is typically detected in the later stages of the disease, but the new method would allow for a diagnosis to be made sooner.</TD></TR></TBODY></TABLE></TD></TR></TBODY></TABLE>Scientists at the University of Guelph say they are developing a means of detecting ovarian cancer -- known as the silent killer -- in its early stages, a breakthrough that could save thousands of lives annually.
Dr. Jim Petrik, a biomedical science professor at the university, and his colleagues are creating a "biomarker" to identify the presence of the disease.
"Ovarian cancer has been termed the silent killer because it progresses without any appreciable symptoms until it is at a very advanced stage," Dr. Petrik said. "The really frustrating thing is that ovarian cancer, in its early stages, is a very treatable disease."
In the diseased mice, as well as in humans, a particular protein, Vascular Endothelial Growth Factor (VEGF), is secreted when cancer cells interact with the ovary.
"The protein is secreted in such high amounts that it is detectable in elevated levels in the blood. It potentially will allow us to develop some screening methods to detect the disease earlier," Dr. Petrik said yesterday.
The researchers are assembling a panel of proteins for a screening test because reliable detection may depend on a combination of proteins.
Dr. Barbara Vanderhyden, chairwoman of the research committee at Ovarian Cancer Canada, said the greatest need against the disease is early detection. So far, it has been an elusive goal.
"Potential biomarkers are being tested ... I'm very hopeful that something will be available in five years," said Dr. Vanderhyden, who is a professor in the department of cellular and molecular medicine at the University of Ottawa.
Researchers at the University of Pittsburgh are finalizing their own panels to detect ovarian cancer; the biomarkers perform at about 96% accuracy, said Dr. Anna Lokshin, lead researcher at the university.
Dr. Petrik and the team at the University of Guelph are also working on a possible treatment involving drugs that can cut off the blood supply to the ovarian tumour. The protein, VEGF, stimulates the creation of new blood vessels which help the tumour grow.
"If we can prevent or inhibit expression of VEGF, we can prevent tumour formation from reoccuring and regress established tumours."
The scientists received $500,000 from the Ontario Institute for Cancer Research in 2005 to study ovarian cancer. They are using a unique mouse model which replicates the early stages of human ovarian cancer.
Prior to the new model, researchers used mice with compromised immune systems and infected them by injecting human cancer cells into the rodents' abdomens. But because the mice had immunodeficiencies, it was not a true representation of disease progression in normal animals, Dr. Petrik said.
Researchers at the University of Guelph now inject cancer cells into the thin tissue surrounding the ovary in healthy mice. Their research will be published in a leading cancer journal, Gynecologic Oncology.
It is not easy to diagnose ovarian cancer. The symptoms in the early stages may be vague.
Later, as the tumour enlarges and cancer spreads, it presses against the bowels or other organs causing symptoms such as diarrhea or constipation, pain or swelling of the abdomen, nausea, gas, bloating and leg or back pain.
Ovan cancer affects about one in 70 Canadian women. About 2,300 Canadian women are diagnosed with ovarian cancer each year and 1,600 women die from the disease.
Some studies have indicated that women may reduce their risk of developing ovarian cancer by using oral contraceptives, giving birth to at least one child, breast-feeding and having a hysterectomy or tubal ligation.