Dendritic cells in bronchial adenocarcinoma

We studied 28 bronchial adenocarcinomas (including 11 bronchiolo-alveolar carcinomas) stained for S-100 protein by the PAP technique in order to visualize dendritic cells in the neoplastic area. Dendritic cells were found in all cases varying in number from single to multiple and from region to region. Bronchiolo-alveolar carcinomas contained a similar quantity of these cells. The most numerous dendritic cells up to several scores per microscopical low-power field almost in all fragments of the tumour were found in three adenocarcinomas with numerous foci of the squamous cell metaplasia. Normal and metaplastic squamous epithelium of the bronchial mucosa did not show the presence of dendritic cells.