Characterization of ERG Gene Rearrangements and PTEN Deletions in Unsuspected Prostate Cancer of the Transition Zone.
Shuhong Liu, Maisa Yoshimoto, Kiril Trpkov, Jeremy A Squire, Qiuli Duan, Tarek A Bismar. Univerity of Calgary and Calgary Laboratory Services, AB, Canada; Kingston General Hospital and Queen's University, AB, Canada; Tom Baker Cancer Center, Calgary, AB, Canada
Background: It was proposed that ERG gene rearrangements and PTEN deletions signify a distinct molecular subtype of prostate cancer (PCA) with adverse prognostic implications. SPINK1 over-expression was also found to be associated with disease progression. Systematic analysis of the incidence of ERG rearrangements, PTEN deletions and SPINK1 over-expression has not been performed in the prognostically favorable transition zone (TZ) PCA.
Design: We interrogated 54 unsuspected PCA tumors obtained by transurtetheral resection of the prostate using fluorescence in-situ hybridization for ERG rearrangements and PTEN deletions. SPINK1 over-expression was assessed by immunohistochemistry.
Results: ERG rearrangements were detected in 6/47 (12.7%) cases with 4/6 occurring by deletion. PTEN deletions were detected in 9/47 (19.1%) cases with only 3/47 (6.4%) having both PTEN losses and ERG rearrangements (p=0.07). SPINK1 over-expression was present in 8/49 (16.3%) and was exclusively restricted to non-ERG rearranged tumors. Only ERG rearrangements were associated with higher tumor volume >5% (p=0.04); PTEN deletions showed similar trends (p=0.06). No assocation was observed between SPINK1 and tumor volume. None of the markers showed association with Gleason score.
Conclusions: ERG rearrangements and PTEN deletions are infrequently found the PCA from the TZ and appear to be less common than in the peripheral zone tumors. TZ and peripheral zone tumors share similar molecular etiologies with different biological behavior based on the rate of ERG and PTEN detection. The infrequent detection of ERG and /or PTEN genetic aberrations in tumors from the TZ may however delineate a subset of tumors with more aggressive behavior. In this cohort, no major differences existed in the incidence of SPINK1 tumors between transition and peripheral zone.
Category: Genitourinary (including renal tumors)
Monday, February 28, 2011 1:00 PM
Poster Session II # 111, Monday Afternoon