ANN ARBOR, MI Like a killer charged with more than one murder, a tiny protein that has already been linked to deadly prostate cancer is now being implicated in lethal breast cancer. And it may soon help doctors tell cancer patients just how dangerous their tumors are.

The double-duty offender, called EZH2, appears to help cancer cells invade nearby tissue and form colonies, according to a new study in the Proceedings of the National Academy of Sciences. This makes it crucial for aggressive, metastatic forms of breast and prostate cancers, both of which are regulated by steroid hormones.

But like many killers who get caught, EZH2 also leaves "fingerprints" -- copies of the protein that can easily be detected in cancerous tissue. In the new study, led by scientists from the University of Michigan Comprehensive Cancer Center, levels of EZH2 in a patient's tumor corresponded to the tumor's level of danger. The more EZH2 there was, the deadlier the cancer and the worse the patient's outcome.

The new results linking EZH2 to breast cancer, and describing the mechanism of its role in cancer's spread, are based on exhaustive analysis of tissue samples and medical records from 280 U-M breast cancer patients, and studies in cell cultures.

The results will be published this week in the online version of PNAS by a team from U-M, the University of Amsterdam and Harvard Medical School. Members of the team previously reported EZH2's role in aggressive and metastatic prostate cancer.

"EZH2 may serve as an excellent biomarker for determining a breast cancer patient's prognosis more precisely than current methods," says lead author Celina G. Kleer, M.D., an assistant professor of pathology at the U-M Medical School. "Just as with prostate cancer, its association with the severity of a patient's disease, and clinical outcome, is striking. And it is easy to
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Contact: Kara Gavin
kegavin@umich.edu
734-764-2220
University of Michigan Health System
8-Sep-2003