The fundamental question about the origin of cancer stem cells of urothelial carcinomas with luminal remains open. So far, no convincing evidence has been found to determine whether these events occur in a single cell, presumably basal, or are realized in different precursor cells of the urothelium. The potential of a number of potential stem markers as cancer stem cells in urothelial carcinomas and their prognostic significance are currently being investigated.
Aim. Our aim was to carry out a comparative analysis of the expression of stem markers in the molecular subtypes of urothelial carcinomas, including ALDH1A1, CXCR4, CD24, CD82, CD105, CD133, NANOG, OCT4 and SOX-2. In addition, the relationship between the pattern of expression and the pathological features of the tumor was determined.
Patients and methods. Surgical specimens from 196 patients with a diagnosis of urothelial carcinoma of the renal pelvis and bladder were studied. Immunohistochemical study was performed on paraffin sections using the standard protocol. Antibodies against ALDH1A1, CD82, CD133, CXCR4, NANOG, OCT4, SOX2 («Abcam»), CD24, CD105 («Invitrogen»), CD31, CD34 («Novocastra») were used.
Results. The stem cell markers used in the study were expressed in all molecular subtypes of urothelial carcinoma and there were no differences in frequency and intensity of expression between different phenotypes. However, the frequency and intensity of expression of the markers correlated with the tumor stage and the grade of cellular anaplasia.
Conclusion. Our results confirm that cancer stem cells with basal phenotype are not an exclusive subpopulation in urothelial tumors. Other progenitor cells with the immunophenotype of intermediate and/or umbrella cells can serve as cancer stem cells. These features of the expression in cancer stem cell markers will allow to develop new approaches to the treatment of urothelial carcinomas.

Keywords: cancer stem cells, intratumoral heterogeneity, urothelial carcinoma