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[Molecular heterogeneity of hCG in urine of the patients with trophoblastic diseases]
T Kitajima1, M Mochizuki, R Nishimura
1Department of Obstetrics and Gynecology, Kobe University School of Medicine.
Insights
Measuring whole human chorionic gonadotropin (hCG) in serum, not urine, is recommended for monitoring trophoblastic diseases. Ratios of hCG variants may aid in differential diagnosis.
Area of Science:
- Biochemistry
- Oncology
- Immunology
Context:
- Trophoblastic diseases, including hydatidiform mole and choriocarcinoma, involve abnormal cell growth related to pregnancy.
- Human chorionic gonadotropin (hCG) and its related molecular forms are key biomarkers in these conditions.
- Accurate measurement of hCG variants is crucial for diagnosis and monitoring.
Purpose:
- To simultaneously measure whole hCG, free hCG beta, and beta-core fragment in serum and urine of patients with trophoblastic diseases.
- To evaluate the utility of these markers and their ratios in differentiating between hydatidiform mole and choriocarcinoma.
- To determine the optimal specimen type (serum vs. urine) for whole hCG measurement.
Summary:
- Whole hCG, free hCG beta, and beta-core fragment were measured using sensitive sandwich enzyme-immunoassays (EIA).
- Serum whole hCG levels were approximately twice those in urine, with strong correlations between both specimen types.
- Free hCG beta levels were low compared to whole hCG, but the free hCG beta/whole hCG ratio was significantly higher in choriocarcinoma.
- Beta-core fragment was detectable only in urine, contributing substantially to urinary hCG beta-immunoactivity (40% in hydatidiform mole, 70% in choriocarcinoma).
Impact:
- Recommends serum measurement of whole hCG as a superior tumor marker for trophoblastic diseases compared to urine.
- Suggests that the ratios between whole hCG, free hCG beta, and beta-core fragment can serve as valuable indices for differential diagnosis.
- Highlights the distinct patterns of hCG variant excretion in serum and urine, aiding clinical management.
Abstract:
In addition to whole hCG, hCG beta-related molecular species are also present in the serum and urine of patients with trophoblastic diseases. We simultaneously measured whole hCG, free hCG beta and beta-core fragment in the serum and urine of patients with hydatidiform mole and choriocarcinoma by the highly specific and sensitive sandwich enzyme-immunoassay (EIA) systems using two kinds of antibodies. During the clinical courses of patients, although the whole hCG levels in serum and urine were closely correlated, the concentrations in the serum were almost twice as high as those in the urine. The free hCG beta levels were also closely correlated in serum and urine, but the concentrations of free hCG beta were extremely low as compared with those of whole hCG. Furthermore, free hCG beta/whole hCG ratios were significantly higher in choriocarcinoma patients than in hydatidiform mole patients. While whole hCG and free hCG beta were contained in both serum and urine, the beta-core fragment could be detected only in the urine of the patients. The relative contribution of the beta-core fragment to the total urinary hCG beta-immunoactivity accounted for about 40% in hydatidiform mole and about 70% in choriocarcinoma. We conclude that whole hCG should be measured in the serum rather than in the urine as a tumor marker for trophoblastic diseases, and suggest that the ratios of whole hCG, free hCG beta and beta-core fragment to each other may be useful indices to employ in the differential diagnosis of trophoblastic diseases.