Biomarkers warn of a “silent killer”
High or low levels of certain proteins can signal the likelihood of ovarian cancer.

Epithelial ovarian cancer ranks as the most lethal of gynecological malignancies. It is only 10 percent as common as breast cancer, but its mortality rate is three times as high. The reason is simple: routine mammography and breast examinations can catch breast cancer early, but no such screening exists for ovarian cancer in its early stages. With few early symptoms, the disease passes under the medical radar until it has reached later stages of malignancy, and therapeutic options are often limited.

Now a group headed by Gil Mor, M.D., Ph.D., associate professor of obstetrics, gynecology and reproductive sciences, has found a way to detect the “silent killer” in its earliest stages, according to a report in May in the Proceedings of the National Academy of Sciences. The researchers devised a screening test that measures levels of six cancer-related proteins—leptin, prolactin, osteopontin and insulin-like growth factor II (IGF-II), Macrophage Inhibitory Factor (MIF) and CA-125—in blood samples. These biomarkers are proteins that change in response to several different forms of cancer, perhaps as part of the immune response. “Our strategy is unique in that we are using a combination of proteins representative of how the total system reacts to cancer, rather than focusing on one protein,” said Mor. Previous studies had identified each of the six proteins as possible biomarkers, but Mor’s team found that individually none of the proteins served as a reliable indicator of cancer.

In a preliminary study of more than 500 women, the screen accurately detected ovarian cancer in 99 percent of cases. The specificity of the test—those correctly diagnosed as disease-free—also stood at 99.76 percent.

Publications describing the screening tests:

Gil Mor, Irene Visintin, Yinglei Lai, Hongyu Zhao, Peter Schwartz, Thomas Rutherford, Luo Yue, Patricia Bray-Ward, and David C. Ward. Serum protein markers for early detection of ovarian cancer, PNAS 2005:102 (2), 7677–7682.

Visintin, I., Alvero, A., Lai, Y., Tenthorey, J., Leiser, A., Flores, R., Rutherford, T., Schwartz, P., Ward, D., Mor, G. Diagnostic Markers For Early Detection Of Ovarian Cancer. Clinical Cancer Research 2008:14 (4), 1065-1072.

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