[1221] PSMA Is Highly Expressed in Gynecologic Tumor Neovasculature, but Lacks Expression in Normal Tissues

Edyta C Pirog, Gabriella Wernicke, Neil H Bander. Weill Cornell Medical College, New York, NY

Background: Prostate-specific membrane antigen (PSMA) has been reported to be uniquely expressed in neovasculature of malignant tumors but not in the endothelium of normal tissues. The goal of the study was to examine whether neovasculature of cervical, endometrial, ovarian and vulvar carcinoma expresses PSMA.
Design: The study cases included normal cervix (n=12), cervical squamous cell carcinoma (n=19), cervical adenocarcinoma (n=8), endometrioid adenocarcinoma of endometrium (n=23), vulvar squamous cell carcinoma (n=20), ovarian serous adenocarcinoma (n=24). Immunostaining was performed using anti-CD31 (clone 1A10; Novocastra) or anti-PSMA antibody (clone 3E6; Dako). The staining was assessed in the tumor and in the surrounding normal tissues. The staining with PSMA antibodies was scored for intensity (0, 1+, 2+, 3+) and semiquantitatively for the percentage of positive intratumoral capillaries with the following brackets: less than 5%, 6% to 25%, 26% to 50%, 51% to 75%, and 76% to 100% positive. CD-31 staining was used as a reference 100% positive control.
Results: PSMA staining positivity was found exclusively in the tumor vasculature and was not seen in neither normal cervix nor in peritumoral normal tissues. The average percentage of tumor capillaries positive for PSMA was 50.6% in cervical cancer, 72.1% in endometrial cancer, 63.8% in ovarian cancers, and 16.1% in vulvar cancer. The stainig intensity of PSMA in tumor vasculature was 2+ to 3+ for cervical, endometrial and ovarian cancer, and 0 to 1+ for vulvar cancer. CD-31 staining was used as a reference positive control, and as expected, was positive in all normal tissues as well as in tumor capillaries.
Conclusions: Prostate-specific membrane antigen is highly and specifically expressed in the neo-vasculature of gynecologic cancers rendering it a potential therapeutic vascular target.
Category: Gynecologic & Obstetrics

Wednesday, March 6, 2013 1:00 PM

Poster Session VI # 209, Wednesday Afternoon

 

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