Immunohistologic localization of corticotrophin-releasing hormone in human tumors

The authors investigated formalin-fixed, paraffin-embedded human tissues for the presence of corticotrophin-releasing hormone (CRH) using the avidin-biotin-peroxidase technic. Immunopositivity was demonstrated in nontumorous hypothalami, 1 of 8 hypothalamic gangliocytomas, 3 of 9 bronchial endocrine tumors, 1 of 30 small cell lung carcinomas, 1 of 8 ileal endocrine neoplasms, 2 of 20 pancreatic endocrine tumors, 2 of 10 medullary thyroid carcinomas, and 1 of 3 small cell prostate carcinomas. Of the tumors containing immunoreactivity, most were associated with Cushing's syndrome; the ileal and thyroid tumors were not. Adrenocorticotrophic hormone was immunohistochemically localized in two bronchial and one pancreatic tumor, which contained CRH-like immunoreactivity. No CRH was detected in nontumorous extrahypothalamic tissues from which the CRH-containing tumors derived, two mediastinal endocrine carcinomas, six endocrine tumors of the stomach/duodenum/appendix, eight pheochromocytomas, one Merkel cell tumor, and 32 squamous and adenocarcinomas of the lung/gut. CRH-like immunoreactivity may be found in tumors composed of peptide-hormone-producing endocrine cells; hypersecretion of CRH by those neoplasms may be significant in the development of Cushing's syndrome.