Somatostatin and adrenocorticotrophic hormone like immunoreactivity in small cell carcinoma of the lung.

The immunocytological detection of adrenocorticotrophic hormone (ACTH) and somatotropin release inhibitor factor (SRIF) like immunoreactivity was carried out on tumour cells from bronchial brush smears in 39 cases of lung tumours. Results obtained were compared with the cytological and histological diagnosis and confirmed the high incidence of ACTH synthesis by malignant bronchial carcinoma cells: the same phenomenon also seems to occur for somatostatin. The concomitant detection of ACTH and SRIF like immunoreactivity seems to be highly suggestive of small cell carcinoma and indicates that the immunocytological detection of hormones carried out at the same time as cytological examination can improve the accuracy of the diagnosis.