[A case of advanced testicular seminoma--chemotherapy and serum marker].

A 52 year-old male with advanced testicular seminoma (stage II N4) underwent right radical orchiectomy, followed by chemotherapy with vinblastine, bleomycin and cis-platinum. This resulted a partial response and he was well for 24 months after the operation. Serial monitoring of serum HCG and HCG-beta has been done, using three kinds of double antibody radioimmunoassays. A substance with immunological similarity to free HCG-beta was detected in sera and tumor extract. The serum level of this substance was reduced in parallel with the cytoreduction of metastasis by chemotherapy. A rational therapeutic approach to advanced seminoma and its serum marker are discussed briefly.