Bombesin, somatostatin and neurotensin-like immunoreactivity in bronchial carcinoma.

Bombesin, a regulatory peptide found in adult lung and in higher concentration during development in the foetal lung, has potent biological actions which include the ability to stimulate the release of a number of hormones. Radioimmunoassay of extracts of tumour, lung and plasma from patients with bronchial carcinoma revealed very high tissue bombesin concentrations in two oat cell carcinomas, with lower levels in two out of six adenocarcinomas exceeding the concentrations found in normal lung. The oat cell carcinomas also contained significant amounts of somatostatin and in one case neurotensin. Neurotensin was further detected in two out of seven squamous tumours and three adenocarcinomas. Secretion of regulatory peptides by bronchial carcinomas may account for some of their ill-understood non-metastatic clinical manifestations.