Composition of Intact Hormone and Free Subunits in the Human Chorionic Gonadotrophin‐like Material Found in Serum and Urine of Patients With Carcinoma of the Bladder

Abstract

Ectopic-hCG production occurs in approximately 30% of urothelial cancers. However, the clinical features which might be expected to result from elevated hCG levels are rare. We now show that in six of seven metastatic and 20 of 21 localized (Ta-T4) positive hCG bladder cancer patients, only the free beta-subunit of hCG and its respective urinary breakdown product, beta-core, could be detected in clinical samples. Since only intact hCG is biologically active, this explains the discrepancy between biochemical and clinical findings.

Detection of Human Chorionic Gonadotrophin-β in Serum or Urine of Prostate Cancer Patients Is of No Clinical Significance

“…This is not the case for prostate cancer: a recent study of 12 readily available cancer cell lines showed that, whilst 2/2 choriocarcinomas, 4/5 bladder cancers and 1/2 endometrial cancer cell lines expressed signifi cant levels of hCG ␤ , none of the 3 prostate cancer cell lines examined expressed detectable levels [27] . Furthermore, the concentrations of hCG ␤ found in this study of prostate cancer patients' serum and urine were considerably lower than those measured in samples from bladder and cervical cancer patients [6,7,9] . The difference between our fi ndings in prostate cancer and those clinical associations found in bladder cancer and renal cell carcinoma may refl ect the different embryological origin or biological behaviour of the tissues involved [28] .…”

“…The ectopic production of free hCG ␤ in the absence of the alpha subunit is a well-recognized phenomenon in many epithelial tumours, in particular of those arising from the urogenital system [6,7,[9][10][11][13][14][15] . Studies of hCG ␤ expression by urothelial tumours and more recently renal cell carcinoma indicate a role for hCG ␤ as a prognostic marker and suggest a biological mechanism whereby free hCG ␤ modulates cell growth [8,16,17] .…”

The beta-subunit of human chorionic gonadotrophin exists as a homodimer

“…The ectopic production of free hCG is a well-recognised phenomenon in many epithelial tumours (Iles et al 1990). Expression of hCG by these cancers was originally thought to carry no biological significance, but it is now apparent that this event may significantly affect tumour development given the growth effects described recently (Gillott et al 1996).…”

British Association for Cancer Research/Association of Cancer Physicians/Royal Society of Medicine (Oncology Section) Joint Winter Meeting Including Symposia on 'Cutaneous Melanoma' (Incorporating the 11th Gordon Hamilton-Fairley Memorial Lecture) and 'Bladder Cancer' (Incorporating the 8th Alexander Haddow Memorial Lecture)

“…Immunochemical analysis of samples from this study showed that only one of seven metastatic patients and one of 21 patients with disease limited to the bladder, produced intact hCG. Since only the intact hCG a-P hetrodimer is biologically active; this explains the discrepancy between the high incidence of immunoreactive hCG expression by bladder tumours and the rarity of gonadotrophin associated clinical endocrinopathies (Iles et al, 1990).…”