Identification of somatostatin receptors in human small cell lung carcinoma.

Biopsy specimens obtained from eight patients with lung cancer were tested for content of somatostatin receptors by autoradiography. Somatostatin receptors were detected in two of three patients with small cell lung cancer (SCLC) but in none of five patients with non-small cell lung cancer (NSCLC) including adenocarcinoma (two), squamous cell carcinoma (two), and bronchoalveolar carcinoma (one). In those with SCLC, specific somatostatin receptor binding was evidenced only in tumor foci and not in surrounding stroma or normal lung parenchyma. Further tissue characterization by immunoperoxidase staining with the pancytokeratin monoclonal antibody, mAB-lu-5, revealed labeling to all of the NSCLC but to none of the SCLC specimen. Selective immunoreactivity was detected in both the SCLC and the NSCLC specimen to chromogranin and neuron-specific enolase (NSE) whereas none of the specimen had detectable immunostaining to somatostatin, bombesin, serotonin, adrenocorticotropic hormone, neurofilament, calcitonin, and synaptophysin. The identification of somatostatin receptors in primary human lung cancer may have a bearing on the biology of this disease and perhaps on the clinical application of somatostatin analogues in patients with SCLC.