Human seriitn pregnancy-specific beta,-globulin (beta,-CP) was localized in parafin sections of placenta and chorioepithelioma of the uterus by indirect itiitnrinoflrrorescence. The structures containing beta,-CP but not human serum albumin were regarded as specifcally associated with beta,-GP metabolism. Beta,-GP was found in trophoblastic cells of chorioti an-i Latrghans cells of chorioepithelionra. Using the itirmunoautoradiographic method (I1:$,), we only found beta,-CP in sera of patients with trophoblastic tumours: in 74.3 76 of 35 patients with chorioepitheliorna and in 80 of 25 patients with hydatidvornr mole and destructive hydatidiforrn mole. The diagnostic and prognostic SigtriJcance of the initnunochemical test for beta,-GP in trophoblastic tuniours is discussed.
In 1974, human pregnancy-specific beta,-globulin (beta,-GP) was discovered in the sera of pa'ients with trophoblastic tumours (Tatarinov et al., 1974 a, b). In earlier investigations ) beta,-GP was found in the sera of pregnant women as well as in placenta extracts but not in normal non-pregnant women or in male donors. Moreover, it was shown that beta,-GP had no immunochemical identity with known hormones including chorionic gonadotropin (Tatarinov et a / . , 1974~).