Human chorionic gonadotropin (HCG) and alpha-fetoprotein (AFP) in sera and tumor cells of patients with testicular seminoma: a prospective study.

The HCG and AFP have been quantitated in the sera of 130 patients with the diagnosis of testicular seminoma utilizing a specific double antibody radioimmunoassay. These tumor markers also were localized in tumor cells of some of these patients utilizing an indirect immunoperoxidase technique. 11 of 130 patients had elevated serum levels of HCG. The HCG molecules have been localized in the syncytiotrophoblastic giant cell (STGC) that is occasionally observed in seminomas. None of the patients with pure seminoma had an elevated level of serum AFP. We have concluded that in patients with pure seminoma the level of serum HCG can be elevated (10 of 130 or 7.6%), but we have not observed elevated serum levels of AFP in these patients.