Ultrastructural peculiarities of intercellular junctions in bronchopulmonary carcinomas.

Six bronchopulmonary carcinomas of various histological types (macrocellular, epidermoid) were electronmicroscopically studied on bronchial biopsy samples. The scarcity of intercellular junctions was observed in all of them, especially in carcinoma types or zones (i.e. of epidermoid carcinoma) less differentiated. Close and gap junctions, zonulae adherentes and maculae adherentes dominated the structure of poorly differentiated carcinomas, while the differentiated types also presented frequent desmosomes. Also the reduction of intercellular junctions frequency was accompanied by their ultrastructural aberrations. The ultrastructural changes observed were correlated to the capacity for invasion of investigated carcinomas without reducing this basic property of cancer cells to the former.