Elevation of free beta subunit of human choriogonadotropin and core beta fragment of human choriogonadotropin in the serum and urine of patients with malignant pancreatic and biliary disease.

Human choriogonadotropin (hCG), its free beta subunit (beta hCG), and the core beta hCG fragment (c beta hCG) were measured by highly sensitive time-resolved immunofluorometric assays in the serum and urine of 29 patients with pancreatic cancer, 7 patients with biliary cancer, and 45 patients with benign pancreatic or biliary diseases. The results were compared with those of an age- and sex-matched reference population of nonpregnant women and men. Of the various forms of hCG assayed in serum, beta hCG showed the best diagnostic accuracy, and c beta hCG was the best marker in urine. Elevated serum concentrations of beta hCG were observed in 72% of the patients with pancreatic cancer, in 6 of 7 patients with biliary cancer, and in 9% of those with benign disorders. The serum concentrations of c beta hCG were elevated in 45%, 57%, and 2%, respectively, and those in urine in 55%, 71%, and 11%, respectively. The molar concentrations of c beta hCG in serum were mostly lower than those of beta hCG. Thus beta hCG secreted into serum appears to be the main source of c beta hCG in urine. Provided that they are measured by sufficiently sensitive and specific assays, beta hCG in serum and c beta hCG in urine appear to be useful markers for pancreatic and biliary cancer.