IMMUNOHISTOCHEMICAL STUDY OF METALLOTHIONEIN IN HUMAN TESTICULAR TUMORS

The localization of metallothionein (MT) in twenty-nine cases of testicular tumor was investigated using an immunoperoxidase method. Fifteen patients had typical seminoma in the primary tumor, two showed seminoma with embryonal carcinoma, one seminoma with choriocarcinoma, three embryonal carcinoma, two teratocarcinoma, three immature teratoma, one teratoma with yolk sac tumor, one teratoma with malignant transformation, one malignant lymphoma, and three metastatic retroperitoneal tumors. Positive immunoreactivity for MT was observed in embryonal carcinoma, well differentiated tissue (cartilaginous cells, gastrointestinal and respiratory mucosa, squamous epithelium), tumor cells differentiated into neural and muscular cells in teratocarcinoma, and differentiated embryonal carcinoma cells in immature teratoma. Tumor cells remaining after chemotherapy including cisplatin showed positive immunoreactivity for MT. However, seminoma cells showed almost no immunoreaction. The present study suggested that MT is detected in well differentiated cells of testicular tumors and may be useful marker for drug resistance.