ABSTRACT
The changes in the synthesis of pregnancy, placental, and endometrial proteins during pregnancy are governed by complex interactions, the majority of which remain as yet unidentified. The local infiltrative capacity of trophoblastic tissue is reminiscent of tumor growth. Local infiltrative capacity, rapid cell division, and increased energy metabolism are identifiable both in pregnancy as well as in tumors. Human Chorionic Gonadotropin (hCG) an outstanding tumor marker for trophoblastic diseases and its use has long been in medical practice. Because it is a placental protein hormone, its presence in the blood of nonpregnant subjects indicates an ectopic secretion. However, the definition of ectopic synthesis must be modified, since extremely sensitive and highly hCG-specific radioimmunoassays may detect concentrations of 4.0 to 36 pg/ml in the serum of healthy nonpregnant women or even in men. The association of high serum AFP levels with teratocarcinoma of the ovary and the testis was similarly first observed by Abelev et al.
