Mesothelin Antibodies Occur In Some Women With An Epidemiologic Risk For Ovarian Cancer.

Researchers at Rush University Medical Center discover mesothelin antibodies in the bloodstream of infertile women, who possess a higher risk of ovarian cancer.

Using a new approach to developing biomarkers for the very early detection of ovarian cancer, researchers at Rush University Medical Center have identified a molecule in the bloodstream of infertile women, who possess a higher risk of ovarian cancer. This finding may be relevant in the future for screening women at high risk for the disease — or even those with early-stage ovarian cancer.

The molecule — an antibody that the human body manufactures — is an autoimmune response to mesothelin. Mesothelin a well-characterized ovarian cancer antigen and protein which is found in abundance on the surface of ovarian cancer cells, but present only in limited amounts in normal human tissue.

The study is published in the August 16 online version issue of Cancer Epidemiology, Biomarkers & Prevention, published by the American Association for Cancer Research (AACR).

Judith Luborsky, Ph.D., Lead Study Author; Professor, Pharmacology, Obstetrics & Gynecology and Preventive Medicine, Rush Medical College

“The finding is extremely important because at present medical tests are unable to detect ovarian cancer in its early stages, which is why death rates from this disease are so high,” said Judith Luborsky, Ph.D., professor of pharmacology, obstetrics and gynecology and preventive medicine at Rush and the lead author of the study.

“Our approach to discovering cancer biomarkers was unique in this study. Instead of investigating molecules specific to ovarian cancer alone, we asked what molecules women with a risk of ovarian cancer and those with ovarian cancer had in common,” Luborsky said.

The study may have enabled the researchers to explain, in part, the link between infertility and ovarian cancer that has been established in numerous epidemiological surveys.

“More important, with the discovery of the mesothelin antibody, we now have what appears to be a biomarker that can potentially be used in screening tests to help us conquer ovarian cancer,” Luborsky said.

According to the American Cancer Society’s most recent estimates, it is anticipated that 21,900 new cases of ovarian cancer will be diagnosed in the U.S. in 2011, and approximately 15,460 deaths will occur in connection with the disease. Ovarian cancer is the ninth most common cancer in women (not counting skin cancer) and ranks as the fifth highest cause of cancer death in women. It is the most lethal gynecologic cancer. The poor prognosis for women with ovarian cancer is due to the lack of both clinical symptoms when the cancer first develops and the absence of laboratory tests specific to the disease.

In the study at Rush, researchers tested for mesothelin antibodies in the bloodstream of 109 women who were infertile; 28 women diagnosed with ovarian cancer, 24 women with benign ovarian tumors or cysts, and 152 healthy women. Causes of infertility included endometriosis, ovulatory dysfunction, and premature ovarian failure. Some causes of infertility were unexplained.

Significant levels of mesothelin antibodies were found in women with premature ovarian failure, ovulatory dysfunction and unexplained infertility, as well as in women with ovarian cancer. The same results were not found in women with endometriosis, good health, or benign disease. Endometriosis is generally associated with the clear cell and endometrioid subtypes of epithelial ovarian cancer, as compared to other forms of the disease associated with infertility, which may explain why mesothelin antibodies were not found in the endometriosis cases.

It is important to emphasize that the explanation as to why the presence of mesothelin antibodies in the bloodstream should be linked with ovarian cancer is not clear.

“It has been hypothesized that an autoimmune response precedes or somehow contributes to the development and progression of malignant tumors,” Luborsky said. “We think that antibodies may arise in response to very early abnormal changes in ovarian tissue that may or may not progress to malignancy, depending on additional triggering events. Or, alternatively, antibodies may bind to normal cells in the ovary, causing dysfunction and leading to infertility — and, in a subpopulation of women, to the development of ovarian cancer.”

Other researchers involved in the study were Yi Yu, MS, and Seby Edassery, MS, both from Rush, as well as a group led by Ingegerd Hellstrom, M.D., Ph.D., and Karl Eric Hellstrom, M.D., Ph.D., which included Yuan Yee Yip, BS, Jade Jaffar, BS, and Pu Liu, Ph.D. from Harborview Medical Center at the University of Washington.

The study was supported by funding from the National Institutes of Health and Fujirebio Diagnostics, Inc.

About Rush

Rush is a not-for-profit academic medical center comprising Rush University Medical Center, Rush University, Rush Oak Park Hospital and Rush Health.

Rush’s mission is to provide the best possible care for its patients. Educating tomorrow’s health care professional, researching new and more advanced treatment options, transforming its facilities and investing in new technologies—all are undertaken with the drive to improve patient care now, and for the future.

Sources:

  • Luborsky JL, et al. Autoantibodies to Mesothelin in Infertility. Cancer Epidemiol Biomarkers Prev. 2011 Aug 16. PubMed PMID: 21846819 [Epub ahead of print]
  • Researchers at Rush University Medical Center Discover Antibody That May Help Detect Ovarian Cancer in its Earliest Stages, News Release, Rush University Medical Center, August 16, 2010.

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