Expression of HER-2/neu in testicular tumors.

Although the overexpression of the Epidermal Growth Factor Receptor 2 (EGFR-2, HER-2/neu, c-erbB-2) in malignancies might predict chemoresistance and poor prognosis, its clinical relevance has not been widely studied and determined in testicular tumors.Since teratomas are relatively chemoresistant tumors, we evaluated the HER-2/neu receptor status of 28 primary testicular tumors (7 pure teratomas, 21 mixed germ cell tumors containing teratomatous components) using a standardized immunohistochemical method (HercepTest Kit).Seven (25%) out of 28 non-seminomatous germ cell tumors showed HER-2/neu positivity. The teratomatous components of mixed GCTs showed HER-2/neu overexpression in 5 cases. Three of the 5 choriocarcinoma components of mixed tumors overexpressed HER-2/neu. In one case (teratoma + choriocarcinoma) both components showed HER-2/neu overexpression. No HER-2/neu overexpression was detected in other, less differentiated histological subtypes. Among the HER-2/neu-positive cases, 3 patients are in complete remission, 3 patients are in partial remission and one patient died after primary chemotherapy.Twenty-five percent of the non-seminomatous germ cell tumors which contain teratomatous components overexpress HER-2/neu protein. The overexpression is restricted to the more differentiated histotypes. Further molecular investigations and clinicopathological studies are necessary to determine the correlation between HER-2/neu overexpression and clinical resistance of testicular tumors.