Autoradiography of cellular glycoproteins reveals histogenesis of bronchogenic adenocarcinomas

Primary and metastatic bronchogenic adenocarcinomas, excluding bronchioloalveolar and large cell types, and normal bronchi were studied to find out if the tumors displayed a common type of glycoprotein metabolism that was also shared by one or more bronchial epithelial cell types. For comparison, the glycoprotein metabolism of a metastatic pancreatic adenocarcinoma was also investigated. Tissues were maintained in vitro, and the cellular distribution of glycoproteins, metabolically labelled with 3H-glucosamine, was determined by light and electron microscopic autoradiography. Intense reactions in the form of silver grains over luminal surfaces of primary bronchogenic adenocarcinomas and those metastatic to pleural fluids indicated that the synthesis of cell coat (glycocalyx) glycoproteins predominated. In the pancreatic adenocarcinoma, the synthesis of secretory glycoproteins predominated, reflecting a histogenesis from secretory epithelium. In bronchi, only ciliated epithelium exhibited a distribution of newly synthesized glycoproteins similar to that observed in the bronchogenic adenocarcinomas. These observations suggest that bronchogenic adenocarcinomas share a common histogenesis and most likely arise from a cell type committed to differentiation into ciliated epithelium.