[Clinical evaluation on differential quantitation of human chorionic gonadotropin in testicular cancer]

In 113 patients with testicular germ cell tumor, the authors determined human chorionic gonadotropin (hCG) and the free beta subunit levels in sera by differential quantitation using homologous hCG-beta radioimmunoassay (RIA) and hCG enzyme immunoassay (EIA), respectively. In 59 patients with seminoma, intact hCG was positive in 6 patients (10.1%), whereas free hCG-beta was positive in 23 patients (39.0%). Syncytiotrophoblastic giant cells were detected in 4 cases out of 6 patients with positive intact hCG seminoma. Seventeen cases (28.8%) revealed positive free hCG-beta only without elevation of intact hCG. In 54 patients with nonseminoma, both intact hCG and free hCG-beta were positive in 36 cases (66%). In some cases, hCG-beta/hCG ratio increased up to 275% when recurrence of tumor developed. Molecular heterogeneity of hCG is closely related to proliferation and differentiation of hCG producing cells. The differential quantitation of intact hCG and hCG-beta using these two assays is valuable for clinical detection of molecular heterogeneity of hCG in testicular tumor.