[969] ERG Rearrangement as a Marker To Differentiate between Small Cell Lung Cancer and Small Cell Prostate Cancer

VJ Scheble, M Braun, T Wilbertz, AC Stiedl, K Petersen, D Schilling, G Seitz, F Fend, G Kristiansen, S Perner. University Hospital Tuebingen, Tuebingen, Germany; Klinikum of the Sozialstiftung Bamberg, Bamberg, Germany; University Hospital Zurich, Zurich, Switzerland

Background: Small cell prostate cancer is a rare but aggressive disease. Currently, its histogenetic origin is unclear and its distinction from metastatic small cell lung cancer is challenging. The aim of our study was to determine whether the ERG rearrangement commonly observed in acinar prostate cancer can distinguish small cell prostate cancer from small cell lung cancer samples.
Design: We assessed 15 small cell prostate cancers and 22 small cell lung cancers for ERG rearrangement using FISH. Commonly used and novel immunohistochemical markers (i.e. AR, CANT1, GOLPH2, PSA, PSMA, CD56, EMA, TTF1, Chromogranin A, Synaptophysin and Ki-67) were further studied.
Results: ERG rearrangement occurs in 86% small cell prostate cancers but in none of the small cell lung cancers. The prostate targeting markers AR, CANT1, PSA, and PSMA were positive in a minority of small cell prostate cancer samples but none of the small cell lung cancer samples whereas GOLPH2 was positive in the majority of both entities. CD56, EMA, and TTF1 were negative in most small cell prostate cancer samples and positive in the majority of small cell lung cancer samples. Thus, ERG rearrangement is the best marker to differentiate between both tumours (p<0.0001).
Conclusions: The ERG rearrangement is commonly observed in small cell prostate cancer supporting the hypothesis that ERG rearrangement occurs in aggressive prostate cancers. Furthermore, the ERG rearrangement is the most significant marker to differentiate between small cell prostate cancer and small cell lung cancer. Moreover, our data suggest that small cell prostate cancer is not a tumour entity on its own but a dedifferentiated variant of common acinar prostate cancer.
Category: Genitourinary (including renal tumors)

Monday, March 22, 2010 1:00 PM

Poster Session II # 108, Monday Afternoon


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