title: Immunological recognition and clinical significance of nicked human chorionic gonadotropin in testicular cancer.
abstract: We studied the physical properties, immunological recognition, and clinical significance of nicked human chorionic gonadotropin (hCGn) in testicular cancer. Upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing conditions, the beta-subunit of hCGn (hCG beta n) dissociated into two peptides, and, by reversed-phase chromatography, hCG beta n was found to be less hydrophobic than hCG beta. Immunologically, hCGn lacked two epitopes specific for holo-hCG (c1, c2), whereas at least five hCG beta epitopes (beta 1-beta 5) were preserved, and, as a result, recognition of hCGn by different hCG assays varied widely. In 309 sera and 88 urine samples from patients with seminomatous or nonseminomatous testicular cancer, hCG-only, hCG+hCGn, and hCG+hCGn+hCG beta+hCG beta n+hCG beta core-fragment assays gave parallel results. hCGn was more abundant in urine than in serum samples. In conclusion, hCGn lacks two conformationally dependent epitopes of hCG, causing a change in hydrophobicity and explaining its failure to react in certain holo-hCG assays. Recognition of hCGn, however, does not seem to be crucial in the routine use of serum hCG as a tumor marker in patients with testicular cancer.
authors.affiliation: Department of Endocrinology, University of Essen, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Hoermann
authors.forename: P
authors.initials: P
authors.lastname: Berger
authors.forename: G
authors.initials: G
authors.lastname: Spoettl
authors.forename: F
authors.initials: F
authors.lastname: Gillesberger
authors.forename: A
authors.initials: A
authors.lastname: Kardana
authors.forename: L A
authors.initials: LA
authors.lastname: Cole
authors.forename: K
authors.initials: K
authors.lastname: Mann
mesh_terms: D055598:Chemical Phenomena; D002627:Chemistry, Physical; D006063:Chorionic Gonadotropin / Q000032:analysis* / Q000097:blood / Q000737:chemistry / Q000276:immunology / Q000652:urine; D018997:Chorionic Gonadotropin, beta Subunit, Human; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D000939:Epitopes / Q000032:analysis / Q000276:immunology; D005260:Female; D006801:Humans; D007118:Immunoassay; D008297:Male; D010446:Peptide Fragments / Q000097:blood / Q000652:urine; D011247:Pregnancy; D018239:Seminoma / Q000378:metabolism; D013736:Testicular Neoplasms / Q000097:blood / Q000378:metabolism* / Q000652:urine
chemical_list: D006063:Chorionic Gonadotropin; D018997:Chorionic Gonadotropin, beta Subunit, Human; D000939:Epitopes; D010446:Peptide Fragments