Endocrine assay in chorionic tumors.

Gestational chorionic tumors represent a rare biologic system for three reasons: They are a genetic mixture of both male and female; they are unusually responsive to chemotherapy with a high cure rate; and they always secrete hCG, which acts as a reliable cell marker with which to diagnose, to monitor drug therapy, and to follow-up to ensure continued remission. Nongestational chorionic tumors characteristically share only the latter unique attribute. For this reason, endocrine assays, particularly the measurement of hCG, play a vital role in the management of patients with these tumors. However, as the tools with which we work improve, and our understanding increases, it is quite likely that other tumors will be found to make substances that are similarly specific and reliable so as to be utilized in the same way. Already there are tests such as alpha-fetoprotein and carcinoembryonic antigen that are beginning to serve such a role but are not as specific as is hCG. Our experience with chorionic tumors has given us a valuable opportunity to develop techniques to be used for other tumor systems when reliable cell markers become available. When this time comes, we should be able to look forward to improved survival rates, hopefully approaching those obtained with chorionic disease.