Peripheral lung carcinoid tumor producing predominantly gastrin-releasing peptide (GRP) morphologic and hormonal studies

Abstract

A carcinoid tumor of the peripheral lung producing gastrin‐releasing peptide (GRP), a peptide hormone known to be present in the endocrine cells of fetal bronchial epithelium, is reported. Brain‐gut peptide hormones in this tumor were assayed by radioimmunoassays, localized by immunohistochemistry and characterized by gel filtration. Electron microscopic study revealed that tumor cells resembled P‐cells of normal human fetal bronchial epithelium. While GRP‐containing cells were predominant in this tumor, calcitonin‐containing cells were also found in some areas. Difference in distribution of hormones according to histologic features was noted in the tumor. A greater portion of the tumor showed spindled cells that predominantly contained GRP, and a smaller portion of the tumor showed cells arranged in tubular or trabecular patterns that mainly contained calcitonin. The gel‐filtration pattern of the tumor extracts consisted of two peaks, one of these corresponded to the synthetic replicate of porcine GRP, and another was considered to correspond to C‐terminal fragments of the peptide. Cancer 52:273‐281, 1983.