hCG and hCG subunits as tumour markers in patients with endocrine pancreatic tumours and carcinoids.

Serum levels of hCG, hCG-alpha- and hCG-beta-subunits were measured in 29 patients with APUD-tumours, 16 patients with endocrine pancreatic tumours (EPT) and 13 patients with carcinoids. Twenty out of 29 patients (69%) had elevated level of hCG and its subunits. Among patients with EPT, 11 out of 16 (69%) had raised levels of these peptides. Three patients with benign tumours had normal concentrations, thus giving a frequency of 85% in the group of malignant EPT. In patients with carcinoids 9 out of 13 (69%) had elevated serum levels of at least one of the components. A discordance in secretion pattern between the two types of APUD-tumours was noticed. Only one patient, a case with a carcinoid had raised levels of the complete hCG molecule. The levels of hCG-alpha were elevated in 23% of the patients with malignant EPT and 69% of the patients with carcinoids while the corresponding frequencies of raised hCG-beta levels were 69% and 8%, respectively. Three out of 4 patients with so-called non-functioning islet cell tumours had raised levels of the subunits. These results indicate that hCG subunits are valuable tumour markers in both of these APUD-tumours, and that malignant EPT predominantly secrete hCG-beta- and carcinoids hCG-alpha-subunits.