Expression of chromogranin a protein and messenger RNA and tyrosine hydroxylase protein in paraffin-embedded sections of neuroendocrine neoplasms.

Forty-three neuroendocrine neoplasms were analyzed by immunohistochemistry for tyrosine hydroxylase and chrornogranin A and by in situ hybridization (ISH) for chrornogranin A messenger RNA (mRNA) using formalin-fixed paraffin-embedded tissue sections. These included pheochromocytomas (7), medullary thyroid carcinomas (5), small-cell lung carcinomas (5), olfactory neuroblastomas (5), neuroblastomas (10), ganglioneuroblastomas (5), and ganglioneuromas (6). Tyrosine hydroxylase was detected in all groups of tumors except the small-cell lung carcinomas, whereas immunoreactivity for chromogranin A protein was detected in all groups.