[978] The Utility of Novel ERG/P63 Cocktail in the Diagnosis of Limited Cancer in Prostate Needle Biopsies.

Oksana Yaskiv, Kelly Simmerman, Susan Zhang, Tom Daly, Huiying He, Sara Falzarano, Longwen Chen, Cristina Magi-Galluzzi, Ming Zhou. Cleveland Clinic, OH

Background: Diagnosis of limited cancer can be challenging in prostate needle biopsies and immunohistochemistry is commonly used in such settings. Recently, TMPRSS2:ERG gene rearrangement was found to be highly specific for and was present in approximately 50% of prostate cancer. Immunohistochemical results using a novel anti-ERG antibody highly correlated with TMPRSS2:ERG gene rearrangement status. We developed an immunohistochemical cocktail containing both ERG and basal cell marker P63 antibodies and evaluated its utility in the diagnosis of limited cancer in prostate needle biopsies.
Design: Sixty prostate biopsies (PBx) containing cancer occupying ≤ 10% of the length of only one core out of the entire biopsy tissue were selected and stained with a cocktail containing ERG and P63 antibodies. ERG positivity and its staining intensity in cancer and benign lesions were recorded.
Results: ERG expression was detected in 38% (23/60) of cases, with strong, moderate and weak staining intensity in 78%, 13% and 9% cases, respectively. The staining was uniform in 87% cases and heterogeneous in 13% cases with different staining intensities in ≥ 25% of cancer cells. High grade prostatic intraepithelial neoplasia (HGPIN) was present in 15 out of 60 PBx and 4 (26%) HGPIN lesions were positive for ERG. They were all adjacent to cancer glands. Benign lesions, present within the PBx cores, including simple and partial atrophy, and basal cell hyperplasia, were negative for ERG. P63 was negative in all cancer glands and positive in benign lesions and HGPIN.
Conclusions: ERG protein expression was detected in 38% of limited cancer in prostate biopsies. It was also detected in 26% of HGPIN lesions, all of which were immediately adjacent to cancer. ERG immunoreactivity was not found in benign lesions. ERG protein expression is highly specific for prostate cancer. The cocktail containing P63 and ERG provides high sensitivity with P63 and high specificity with ERG and is potentially useful in the work-up of difficult prostate biopsies.
Category: Genitourinary (including renal tumors)

Monday, February 28, 2011 1:00 PM

Poster Session II # 109, Monday Afternoon


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