N-cadherin expression in primary and metastatic testicular germ cell tumors.

Purpose: Upregulation of N-cadherin in epithelial tumor cells has been reported to enhance the invasive process. Although the distribution of N-cadherin in the normal testis was demonstrated, there is no adequate information regarding its presence in testicular germ cell tumors (GCTs). Our purpose was to examine the expression and localization of N-cadherin in germ cell tumors of the testis and share our experience. Methods: 104 adult cases of primary and metastatic testicular GCTs, 5 germ cell neoplasia in situ and 15 benign testicular tissues were included into the study and analyzed for immunoexpression of N-cadherin. Positive expression was evaluated according to intensity and localization of the staining. Results: In 34 pure seminomas, 6 seminomas of mixed component and 16 metastatic seminomas, N-cadherin expression was observed with variable staining intensity. Two pure yolk sac tumors and 20 out of 34 mixed GCTs with yolk sac components were positive for N-cadherin. In contrast, neither the embryonal and chorionic carcinomas nor the teratomas showed N-cadherin expression. Conclusions: N-cadherin immunexpression should be interpreted considering both staining intensity and extent. In case of a metastatic tumor of unknown primary showing prominent N- cadherin expression, seminoma should be considered in the differential diagnosis. At the same time N-cadherin staining could be used to differentiate seminomas from embryonal carcinomas with solid components in metastatic GCTs, both having similar histopathological findings. On the other hand, the diagnostic value is not obvious for nonseminomatous tumors.