Non-seminomatous germ cell tumors of the testis. Immunohistochemical localization and serum levels of human chorionic gonadotropin (HCG) and pregnancy-specific beta-1 glycoprotein (SP-1); value of SP-1 as a tumor marker.

Serum levels of HCG and SP-1 and tissue localization in the primary tumors of these markers were correlated in 41 patients with advanced-stage non-seminomatous germ cell tumors (NSGCT) of the testis. In patients' serum, as well as in the primary tumor tissue, SP-1 positivity was accompanied by a concordant HCG positivity, so that it is concluded that in our patient group SP-1 does not give important additional information with respect to marker positivity not yet provided by HCG. A good correlation was found between serum levels of HCG and SP-1 in advanced-stage disease and the cellular localization of these markers in the primary tumors. Elevated serum SP-1 levels, with concordant elevation of HCG serum levels, were found mainly in cases with a histological diagnosis of choriocarcinoma or an admixture of this component in the primary tumor. Moreover, in cases of choriocarcinoma the presence of SP-1 positive syncytiotrophoblastic cells was very much comparable with the presence of HCG-positive syncytiotrophoblastic cells, whereas in syncytial giant cells associated with embryonal carcinoma HCG-positivity clearly outnumbered SP-1-positivity. This indicates a higher specificity of SP-1 for choriocarcinoma and, therefore, serum levels of this marker may have an important prognostic impact in NSGCT patients with advanced-stage disease. Apart from positivity in syncytiotrophoblastic cells of choriocarcinoma and syncytial giant cells, HCG positivity was incidentally seen in mononuclear embryonal carcinoma cells.