[943] Sensitivity and Specificity of Novel and Contemporarily Used Immunohistochemical (IHC) Markers in the Histologic Typing of Germ Cell Tumors (GCT) of Testis: Implications for Creating a Best Practices Panel Approach

RS Parakh, M Venturina, B Balzer, AM Gown, DE Westfall, M Vankalakunti, MB Amin. Cedars- Sinai Medical Center, Los Angeles, CA; Phenopath Laboratories, Seattle, WA

Background: The distinction between different GCT components has important prognostic and therapeutic ramifications and IHC may play a vital adjunctive role. Recently, several novel markers have been described and studied individually in the spectrum of GCTs. A comprehensive study evaluating the entire spectrum of GCTs with novel and contemporary markers has not been undertaken based on the growing armamentarium of IHC antibodies.
Design: IHC for AE1/AE3, alpha- fetoprotein (AFP), beta-human chorionic gonadotropin (HCG), CD30, C-kit, OCT3/4, Podoplanin, Glypican-3 and OSCAR was performed in 80 primary testicular GCTs (51 mixed GCT and 29 pure GCTs of varying histology). GCT components included 50 intratubular germ cell neoplasia (ITGCN), 37 classic seminoma (CS), 3 spermatocytic seminoma (SS), 42 embryonal carcinoma (EC), 1 pediatric and 40 postpubertal yolk sac tumor (YST), 1 pediatric and 28 postpubertal mature and 28 immature teratoma, and 9 choriocarcinoma (CC).
Results: CS were positive for podoplanin, C-kit and OCT3/4 with sensitivity and specificity of (100%,65%),(100%,81%),(95%,64%) respectively. EC stained with AE1/AE3,OSCAR, OCT3/4 and CD30 with sensitivity and specificity of (100%,16%),(100%,16%),(100%,68%),(97%,96%). YST stained with AE1/AE3,OSCAR, Glypican-3 and AFP with sensitivity and specificity of (100%,16%),(100%,16%),(87%,91%),(77%,100%). SS stained with C-Kit only with a sensitivity and specificity of 100%,73%. CC stained with AE1/AE3, OSCAR and HCG with sensitivity and specificity of (100%, 16%),(100%,16%),(100%,100%). Syncytiotrophoblasts were positive with Glypican-3 and HCG with sensitivity and specificity of (96%,75%), (100%,100%). Immature teratoma stained with AE1/AE3 and Glypican-3 in 21%, 7% cases. OCT3/4 staining was not seen in any of YST, SS, CC, or teratoma; but it showed positivity in all ITGCN with 100% sensitivity.
Conclusions: 1) There is a significant overlap in IHC staining of GCTs which is in keeping with the tetrahedron model and histological continuum of progression of these tumor patterns. 2) Expression of different markers is representative of their biological function and hence the overlap between different GCT components. 3) Sensitivity and specificity data is vital in determining the best panel which should be constructed based on differential diagnostic consideration.
Category: Genitourinary (including renal tumors)

Monday, March 22, 2010 1:00 PM

Poster Session II # 102, Monday Afternoon


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