Hyperglycosylated Human Chorionic Gonadotropin in Serum of Testicular Cancer Patients

BACKGROUND: Hyperglycosylated human chorionic gonadotropin (hCG-h) contains larger and more complex carbohydrate chains than regular human chorionic gonadotropin (hCG). hCG-h is thought to be the major form of hCG produced by testicular cancers and it has been suggested to play a key role in tumor invasion, but studies on hCG-h in testicular cancer are limited. We studied whether serum hCG is hyperglycosylated, and whether measurement of hCG-h in serum offers clinical value in the management of testicular cancer. METHODS: We determined the serum concentrations of hCG-h, hCG, and the free beta subunit of hCG (hCG beta) by time-resolved immunofluorometric assays in 176 serum samples (preoperative n = 67, relapse n = 20, follow-up n = 89) obtained from 84 testicular cancer patients. We analyzed the association between preoperative serum concentrations of hCG, hCG-h, and hCG beta with known prognostic factors and progression-free survival time. RESULTS: A major proportion of hCG was hyperglycosylated preoperatively, at relapse, and shortly after treatment. The serum concentrations of hCG-h and hCG correlated strongly with each other and had similar diagnostic value. The preoperative serum concentration of hCG-h correlated with prognostic factors and outcome in the same way as hCG. Increased preoperative hCG beta concentration predicted shorter progression-free survival. CONCLUSIONS: Most of the hCG expressed by testicular cancers is hyperglycosylated and therefore it is important that hCG assays used for management of testicular cancer recognize hCG-h. (c) 2012 American Association for Clinical Chemistry