Expression of neuropeptides and other neuroendocrine markers in human phaeochromocytomas

Aims: Phaeochromocytomas may produce several neuropeptides as they are cons idered neuroendocrine tumours. Nevertheless, studies are scarce and no clea r predictive biologic value has been stablished in the case of neuropeptide s expression. Methods: We have investigated immunohistochemically the neuropeptides expre ssion of a serie of 36 phaeochromocytomas: 25 sporadic, seven familial type MEN (multiple endocrine neoplasm) and four familial phaeochromocytomas not associated with MEN syndrome. The reactivity for neuron-specific enolase ( NSE), synaptophysin, vasoactive intestinal peptide (VIP), chromogranin A, c alcitonin, ACTH, somatostatin and HMB-45 was tested according to the avidin -biotin complex (ABC) method using polyclonal antibodies. Results: Phaeochromocytomas have a multiple synthetic activity as main neur oendocrine feature. Despite phaeochromocytoma tumour cells heterogeneity ch romogranin and synaptophysin are the most common neuropeptides synthesised, as they are associated with the presence of neuroendocrine storage granule s. We find a statistically significant higher synthesis of corticotrophin h ormone in familial phaeochromocytomas than in sporadic forms, on the contra ry the synthesis of VIP is statistically associated with sporadic forms of phaeochromocytomas. We also found a direct relation of ACTH and overexpress ion and malignant tumours and a positive relationship between NSE and benig n forms of phaeochromocytomas.