[777] Expression of N-Cadherin in Yolk Sac Tumor of the Testis

DJ Heidenberg, M Grinkemeyer, DF Cameron, IA Sesterhenn. Armed Forces Institute of Pathology, Washington, DC

Background: More than half of adult testicular germ cell tumors consist of more than one cell type. Appropriate medical management depends on accurate pathologic diagnosis and tumor classification. Yolk sac tumor (YST) is present in approximately 40 % of mixed germ cell tumors but may be difficult to recognize because it displays several microscopic patterns. In about 75 to 90% of cases -fetoprotein can be detected in the serum or by positive staining in the tumor. The focal positivity can make it difficult to identify and differentiate the YST component. As such, additional markers of endoderm differentiation would be beneficial for the diagnosis and classification of these tumors. N-cadherin is a member of the cadherin gene family that encodes the N-cadherin protein, which mediates cell adhesion. Aberrant expression of N-cadherin by cancer cells, e.g. prostate cancer, can contribute to local invasion and metastasis. The purpose of this study was to determine the presence and distribution of this protein in germ cell tumors.
Design: Thirteen mixed germ cell tumors containing YST components were stained for N-cadherin utilizing immunohistochemistry. The sections were incubated with anti- N-Cadherin mouse monoclonal antibody (Dako North America, Inc., CA, USA) at a dilution of 1:120 for 1 hour, followed by 30 minutes in biotinylated horse antimouse (Vecto, Burlingham, CA) at a dilution of 1:400, and ABC (Vector, Burlingham, CA) Vector VIP was used as chromogen.
Results: All YST components stained positive for N-cadherin. Ten of the 13 were extensively positive, 2 were 3+ positive and 1 tumor had only weak positivity. In contrast, of the 12 tumors containing teratomas, 11 were weakly positive for N-cadherin and 1 was negative. Twelve tumors contained embryonal carcinomas none of which expressed N-cadherin. Eight of the mixed germ cell tumors contained syncytiotrophoblasts cells, none of which stained positive for N-cadherin. Similarly, none of the 6 areas of seminoma expressed N-cadherin.
Conclusions: We conclude that N-cadherin is a useful marker for YST and provides a novel method of identifying the presence of YST component within mixed germ cell tumors, allowing differentiation from seminomas, embryonal carcinomas, and teratoma.
Category: Genitourinary (including renal tumors)

Monday, March 9, 2009 1:00 PM

Poster Session II # 101, Monday Afternoon