Blood Antibody May Signal Start of Ovarian Cancer
WEDNESDAY Aug. 17, 2011 -- Researchers have found an antibody that might someday be useful in identifying women who have a higher risk of ovarian cancer, or possibly diagnosing early ovarian cancer.
This particular antibody, which was detected in blood, develops as an immune system response to a protein called mesothelin. This protein is present in advanced ovarian cancer. Although mesothelin is found in normal tissue, it's found in abundance in ovarian cancer cells.
The current study found that infertile women, who are known to have an increased risk of ovarian cancer, were more likely to have the mesothelin antibody. The researchers also found that women with ovarian cancer were more likely to have this antibody.
"We're taking a novel approach to try to identify earlier biomarkers of ovarian cancer by looking at high-risk women," said study author Judith Luborsky, a professor of pharmacology, obstetrics and gynecology, and preventive medicine at Rush University Medical Center in Chicago.
"This study found that there are antibodies to mesothelin circulating in women that have infertility," noted Dr. Len Lichtenfeld, deputy chief medical officer of the American Cancer Society. Exactly what these findings mean isn't yet clear, however. "Are these women who will develop ovarian cancer? Are these antibodies related to infertility? This research gives us some clues, and leads to many more questions," he said.
As for an individual woman who's currently concerned about ovarian cancer, Lichtenfeld said, "I would be very cautious about drawing any conclusion about the meaning of an elevated antibody level in an individual woman."
Results of the study will be published Aug. 17 in the online version of the journal Cancer Epidemiology, Biomarkers & Prevention.
Almost 22,000 American women are diagnosed with ovarian cancer each year, and more than 15,000 women die each year as a result of this disease, reports the American Cancer Society.
Most women who develop ovarian cancer aren't diagnosed until the disease is advanced. If it's found early, ovarian cancer has a five-year survival rate of 94 percent, according to the cancer society. Two tests that experts hoped would help change that -- a combination of transvaginal ultrasound and a blood test for CA-125, a marker associated with ovarian cancer -- haven't reduced a woman's risk of dying from ovarian cancer, according to a recent study in the Journal of the American Medical Association.
Luborsky and her colleagues wanted to try to find a way to detect early cancer or a screening test for who's at high risk for ovarian cancer before the cancer develops. Testing for mesothelin wouldn't work, because it isn't found at high levels until the cancer is advanced.
So, instead of looking for mesothelin, the researchers looked at a group of 109 infertile women, 28 women with ovarian cancer, and 24 women with benign ovarian cysts or tumors to see if these groups had antibodies to mesothelin. They also compared the three groups of women to healthy women to see if mesothelin antibodies were present.
Significant levels of mesothelin antibodies were found in women with ovarian cancer and in women with unexplained infertility or women who were infertile due to premature ovarian failure or ovulation problems. Women who were infertile due to endometriosis didn't have significant levels of mesothelin antibodies, according to the study. Healthy women, and women with benign ovarian growths also didn't have significant levels of mesothelin antibodies, the investigators found.
"There's a lot more we have to learn, but our aim would be for a screening test that could improve detection," said Luborsky.
Learn more about ovarian cancer from the American Cancer Society.
Posted: August 2011