[Morphofunctional characterization of Apud cells in the human rectum in tumor growth]

Under normal conditions the number and proportion of four main cell types of Apud cells (EC, DI, D, L) is stable. The number of Apud cells is always lower when adenomas or adenocarcinomas are present. A decrease of Apud cells number is inversely proportional to the degree of dysplasia. In parallel, increased proportion of EC-cells occurs, 20-30% as compared to normal condition. A decrease of epithelial tumor differentiation correlation with an increase of ultrastructural signs of active proliferation and Apud cells secretory activity, their degranulation and destruction, appearance of "agranular" and "mixed" endo-endocrine cells.