[Qualitative analysis of the immunoreactive hCG beta-like substance produced by transitional cell carcinoma of the...

The hCG beta-like immunoreactivity (IR-hCG beta) in the sera and urine of three patients with transitional cell carcinoma of the bladder was characterized by enzyme-immunoassay which specifically recognized the hCG beta-related molecular species (whole hCG, free hCG beta and beta-core fragment). There was a qualitative difference in IR-hCG beta between the serum and the urine in all of the patients. Free hCG beta was exclusively detected in the serum, whereas both free hCG beta and beta-core fragment (beta-CF) could be detected in the urine. Whole hCG could not be virtually observed in the sera and the urine from all the patients examined. The concentrations of urinary beta-CF were consistently much higher than those of urinary and serum free hCG beta in all the patients. The immunohistochemical study was performed by using two kinds of the antibody against the core and the carboxyterminal portions of the hCG beta molecule. Immunoperoxidase staining was positive not only in the syncytiotrophoblastic giant cells but also in the transitional cell carcinoma cells for both antibodies. The present results suggest that free hCG beta is secreted from the tumor cells and metabolized into beta-CF may provide a new index to detect a transitional cell carcinoma of the bladder.