Pancreatic polypeptide immunoreactivity in medullary carcinoma of the thyroid: identification and characterisation by radioimmunoassay, immunocytochemistry and high performance liquid chromatography.

Pancreatic polypeptide immunoreactivity has been identified in primary medullary carcinoma of thyroid using radioimmunoassay and immunocytochemistry and subsequently characterised by HPLC. Two region-specific PP antisera were used in the study; one C-terminal and one non-C-terminal. These antisera demonstrate variable cross-reactivity with the molecular species of PP identified in the tumours. The immunoreactive material in the tumours corresponded to human PP and not PYY or NPY on the basis of immunoreactivity and HPLC behaviour. It was identified in all patients with familial-type disease but not in the two sporadic cases examined. We propose that estimation of the PP content of medullary carcinoma of thyroid may be a useful means of differentiating familial and sporadic types.