[884] Expression of ERG Protein, a Prostate Cancer Specific Marker, in High Grade Prostatic Intraepithelial Neoplasia (HGPIN) Detected in Prostate Biopsy: Lack of Utility To Stratify HGPIN Cancer Risks

Huiying He, Adeboye O Osunkoya, Paula Carver, Sara Falzarano, Cristina Magi-Galluzzi, Ming Zhou. Cleveland Clinic, Cleveland, OH; Emory University, Atlanta, GA; Beijing University, Beijing, China; New York University, New York, NY

Background: HGPIN is a premalignant lesion to prostate cancer (PCa). A diagnosis of HGPIN in prostate biopsy (PBx) is associated with a 20-25% of risk of PCa in subsequent PBx. No clinicopathological parameters and biomarkers can reliably identify patients who actually harbor PCa. ERG gene fusion is highly specific for and is identified in 40-50% of PCa and 20% HGPIN which is always associated with ERG-positive PCa. Positive immunostains for ERG highly correlate with ERG gene fusion. We studied whether a positive ERG immunostain in HGPIN could identify patients with PCa on repeat biopsy.
Design: Ninty-four patients with initial HGPIN diagnosis in PBx and at least one follow-up PBx were included. Immunostain for ERG (clone ID: EPR3864) was performed on the initial PBx with HGPIN.
Results: Patients mean age was 63 years (range 48-78). A mean of 1.8 (range 1-5) repeat biopsies were obtained at a mean interval of 27.4 months (range 1.5-140). Repeat PBx showed PCa, benign, HGPIN, atypical glands suspicious for cancer in 36 (38%), 26 (%), 27 (%) and 5 (%) patients. ERG immunostain was positive in 5/94 (5%) PBx with HGPIN, in which PCa was found in 2 (40%) in subsequent PBx. Of 89 initial PBx with negative ERG staining, PCa was found in 34 (38%) repeat biopsies. The cancer detection rate was not different between ERG positive and negative cases (p=0.299).
Conclusions: ERG protein expression is uncommon in HGPIN (5%). PCa was detected at a similar rate on follow-up PBx in ERG-positive HGPIN cases and ERG-negative cases. Our study confirms that ERG expression is of no clinical utility in stratifying HGPIN cancer risks.
Category: Genitourinary (including renal tumors)

Monday, March 19, 2012 1:00 PM

Poster Session II # 174, Monday Afternoon


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