Majority and minority cell populations in GEP and bronchial endocrine tumours.

Gastro-entero-pancreatic (GEP) and bronchial endocrine tumours have been studied by immunohistochemistry using specific antisera against a variety of hormonal and neuronal peptides. In gastrinomas numerous tumour cells were found to contain GH-like immunoreactivity. These cells were identical with those storing gastrin. Gastrinomas as a rule were extremely heterogeneous containing a variety of minority cell populations, including CCK immunoreactive cells and neurotensin immunoreactive cells. Glucagonoma cells were found to store GIP-like material in addition to glucagon. In some insulinomas calcitonin-like material was encountered in the insulin producing tumour cells. In both glucagonomas and insulinomas other pancreatic endocrine cell types constituted minority cell populations. One intestinal somatostatinoma contained gastrin cells as a minority cell population. Bronchial endocrine tumours contained scattered cells displaying ACTH-like or enkephalin-like immunoreactivity. Two such tumours in addition contained cells displaying neurophysin immunoreactivity.