Clinical applications of hCG

Pathophysiological importance of various molecular forms of human choriogonadotropin

Human chorionic gonadotropin (hCG), its subunits and fragments are widely used for diagnostic purposes. In addition to the diagnosis of pregnancy and pregnancy related disorders, hCG determinations are used for diagnosis of trophoblastic and recently also nontrophoblastic tumors. The use for diagnosis of nontrophoblastic tumors requires highly specific and ultrasensitive assays. With these, it is possible to measure the concentrations of both hCG, the free beta-subunits and the so called beta-core fragment in healthy subjects. Therefore it is important to establish reference values for these and also to be aware of the influence of physiological factors on the serum and urine concentrations. Improved standardization of the assay methods is also essential for these novel applications of hCG determinations to become useful.

Evaluation of tumor and trophoblastic marker concentration in breast cyst fluid

In our study we have examined 314 samples of cyst fluid taken from women suffering from fibrocystic breast disease (gross cystic disease). We have subdivided the cyst fluid with respect to epithelial coating and we have related trophoblastic protein content of the cyst fluid with age, seriousness of illness, and cytology of epithelial lining. We have performed RIA analysis of the trophoblastic proteins betahCG, beta1-SP-1, and alphahCG and in a smaller (n=84) group of specimens we have also tested for CEA, TPA, and ferritin. Trophoblastic proteins were positive in cystic fluids but the biological meaning of this is not known and the values are not related to clinical manifestations, except in a group of patients with apocrine metaplasia in which we tried to find a relationship between fertile age and increased betahCG. This finding presumably has a prognostic meaning that can be further understood by epidemiologic studies (of dietary intake and evaluation of lipid metabolites) and by information about inflammatory state of cystic fluid.

Differential production of human chorionic gonadotropin and free subunits in gestational trophoblastic disease

Serum levels of human chorionic gonadotropin (hCG) and its free subunits (alpha hCG and beta hCG) were determined by means of highly sensitive and specific monoclonal and antipeptide-based monoclonal immunoradiometric assays. During normal pregnancy, the beta hCG to hCG ratio appears constant at approximately 0.5% after 5 weeks of gestation. In contrast, gestational choriocarcinoma was characterized by absolute serum beta hCG levels varying from three to 280 times greater than the maximum values observed during pregnancy and by exceedingly high beta hCG to hCG ratios. In complete hydatidiform mole, this ratio was intermediate between normal pregnancy and choriocarcinoma. The ratios of free beta hCG to hCG will distinguish normal from complete molar pregnancy (p less than 10(-8)), hydatidiform mole from choriocarcinoma (p less than 10(-4)), and choriocarcinoma from normal pregnancy (p less than 10(-8)) with high probability. Finally, it was found by means of the high sensitivity hCG immunoradiometric assays (less than 0.02 ng/ml) that this assay predicted very early tumor recurrence in patients with gestational choriocarcinoma.