Applications of biologic tumor markers in testicular cancer.

Quantitative measurement of serum alphafetoprotein (AFP) and human chorionic gonadotropin (HCG) by double antibody radioimmunoassays originally developed at the National Cancer Institute, Bethesda, Md) has been performed in 130 patients with seminoma and in 300 patients with nonseminomatous testicular cancer. Ten of 130 (7.7%) patients with seminoma, 99 of 152 (65%) patients with embryonal carcinoma with or without teratoma, and five of five (100%) patients with pure choriocarcinoma had an elevated level of HCG. None of the patients with seminoma or choriocarcinoma had an elevated level of serum AFP although elevated levels were present in 67% of the patients with embryonal carcinoma with or without teratoma. Either HCG or AFP was elevated in about 90% of the patients with clinically demonstrable embryonal carcinoma with or without teratoma and choriocarcinoma. These two markers have been helpful in staging, detecting recurrence, prognosis, and localization (by the alpha subunit of HCG) of a tumor. Utilizing immunocytochemical techniques, HCG has been localized in syncytiotrophoblastic component of choriocarcinoma. AFP has been localized in yolk sac tumor and embryonal carcinoma cells.