[Electron microscopic analysis of apoptosis of rectal cancer cells before and after irradiation].

Two kinds of tumor cell death--necrosis and apoptosis--were compared upon electron-microscopic study of rectal cancer cells apoptosis before and after the tumor irradiation. Apoptosis in nonirradiated tumor occurs more commonly along its periphery, advanced tumor stages being characterized by apoptosis presentation with phagocytized apoptotic bodies. Upon irradiation the number of apoptotic cells in the tumor tends to increase whereas morphologic pattern of apoptosis remains unchanged.