Background. Programmed cells death, apoptosis, is a physiological, genetically controlled mechanism. It represents the fate of the majority of cells formed during the somatic development and during the next life of most of the creatures. In the article, data from the study of urothelial carcinoma cells are presented and compared with histochemical analysis. Methods and Results. During 1999 to 2002 native urine samples of 36 of patients with the verified urothelial carcinoma were studied. Nine patients had tumors of the grade II, 27 patients had tumors of grade III. Urine samples were analysed by flow cytometry and the data obtained were compared with tumor gradients. In our cohort the zero apoptotic activity was found in 32 patients (88.9 %). In four patients with preserved apoptosis the tumors were of the grade III. Conclusions. Lack of apoptosis of the tumor cells was the dominant sign in our sample. The premise of existing apoptosis in tumors of the lower grade contrary to the higher one was not confirmed when apoptosis was found in four tumors of the grade III. When the tumor grading was compared, apoptosis was less active in the group of tumors with the highest histopathologic grading. Values expressing the direct relation between apoptosis and the histopathologic grading were obtained.

        Key words: apoptosis, urothelial carcinoma, flow cytometry.