Gonadal malignant germ cell tumors express immunoreactive inhibin/activin subunits

Objective: Inhibin and activin are proteins produced by ovarian granulosa cells and testicular Sertoli cells and are members of the transforming growth factor-b superfamily. Since increased circulating levels of immunoreactive inhibin were detected in women with malignant ovarian tumors, they were proposed as tumor markers for ovarian carcinoma. Immunohistochemical studies later confirmed the presence of inhibin and activin subunits in granulosa cell tumors and epithelial ovarian cancer, as well as in Sertoli and Leydig cell testicular cancer. However, there is discrepant information on the detection of inhibin and activin in malignant germ cell tumors (MGCT). The aim of the present study was to evaluate the immunohistochemical expression of the inhibin/activin a, bA and bB subunits in ovarian and testicular MGCT specimens using polyclonal antisera. Methods: The ovarian tissue samples were composed of 19 MGCT, including dysgerminoma \u85n \u88 18\u86 and yolk sac tumor \u85n \u88 1\u86. The testis specimens included classic seminomas \u85n \u88 20\u86; embryonal carcinomas \u85n \u88 7\u86; choriocarcinomas \u85n \u88 2\u86; and yolk sac tumor \u85n \u88 1\u86. Results: Ovarian and testicular malignant germ cell tumors expressed positive staining for inhibin/ activin a, bA and bB subunits, with some variations between and within individual tumors: while ovarian dysgerminomas were diffusely positive for a, bA and bB, testicular tumors expressed a and bB subunits, whereas bA staining was weak. Conclusions: The present results show positive staining for inhibin/activin subunits in ovarian and testicular MGCT, suggesting a possible role in tumorigenesis with the resultant clinical implication