Human chorionic gonadotropin in human neoplastic cells

It seems possible that some form of placental HCG may be involved in the tolerance of the human fetus by the maternal immunologic system. Further attention is focused on this possibility because detectable urinary and serum levels of HCG have been reported in patients with a variety of malignant tumors and because neither fetuses nor tumors are rejected as foreign by their hosts. Previously, preliminary evidence has been presented that material antigenically identical to the β chain of HCG was present in 10 malignant tumors. This report indicates that peroxidase labeled antibody against the β chain of human chorionic gonadotropin was present in 25 out of 28 malignant human tumors of ectodermal, mesodermal and endodermal origins. The antigen was localized both in the cytoplasm and on the surface of the malignant cells. Human chorionic gonadotropin may be responsible for both selective maternal immunosuppression by fetal tissue and host immunosuppression by tumors.