The Prevalence of Glypican3 (GPC3) Expression in Germ Cell Tumors of Testis

Background and purpose: Germ cell tumor is the most common malignancy of men between 15-34 years of age. Proper treatment is highly dependent on accurate histologic diagnosis, and different markers such as cytokeratin, CD3, GPC3 and etc. were proposed. It was reported that GPC3 is over expressed in testicular germ cell tumors by micro array assay. The aim of this study was to evaluate the expression of GPC3 using IHC in all testicular germ cell tumors to assess its possible application as a diagnostic marker. Materials and methods: GPC3 was immunohistochemically assessed among 55 cases of germ cell tumors, including 23 seminoma, 10 embryonal carcinoma, 8 teratocarcinoma, 4 mixed germ cell tumor, 3 mature teratoma, 3 immature teratoma and 4 yolk sac tumors. Results: All yolk sac tumors and yolk sac components of mixed germ cell tumors showed diffuse membranous and cytoplasmic positivity for GPC3. The positive results decreased to 33% , 25% and 20% in immature teratomas, teratocarcinomas and embryonal carcinomas, respectively. No reactivity in seminoma, mature teratoma and normal testicular tissue was seen. Conclusion: It seems that GPC3 is a usefull marker in the histopathologic diagnosis of yolk sac tumors or yolk sac elements of mixed germ cell tumors.