Relevance. The modern approach to prognostication of the course of renal carcinoma requires identification of the biological markers, which determine the key properties of the tumor in particular cases. The purpose of this study is to clarify the nature of expression of the molecules connected with the phenotype of the cancer stem cell (CD133, N-cadherin), TGF-α growth factor for tubular epithelium, and carboanhydrase IX (CA-IX) - one of the key molecules connected with VHL by the molecular way of carcinogenesis in cases of renal cancer. Materials and methods. We studied 61 observations of renal cell carcinoma (RCC). The immunohystochemical examination was based on a panel of antibodies, which included antibodies to TGF-α (Аbcam), N-cadgerin (M3613 clone; Dako), CD133 (Prominin-1, Biorbyt), carboanhydrase IX (CAIX; NCL-L-CAIX, Leica Biosystems). The degree of the markers' expression was evaluated by a semiquantitative method depending on the content of the positive-reaction cells in the tumor. The differences between the compared groups were identified through the use of the Mann-Whitney U test and the chi-squared test. Results. Expression of TGF-α was found in 36 observations (59%) of RCC. TGF-α was most frequently present in the papillary (100%) and the clear-cell (55.9%) versions, and only rarely in chromophobic carcinoma (23.1%). A connection was found between the expression level of this marker and the neoplastic differentiation degree (p < 0.05). Expression of N-cadgerin was met in 38 observations (62.3%), CD133 occurred in 37 observations of renal carcinoma (60.6%). N-cadgerin and CD133 were found in the clear-cell and the papillary versions of RCC. There was a connection between the expression of N-cadgerin in the tumor and its invasive potential (p < 0.05). A higher occurrence rate of CD133 expression was recorded in the patients with metastatic forms of RCC, and also in cases of sarcomatoid transformation of the tumor (p < 0.05). Expression of carboanhydrase IX (CA-IX) occurred in 35 observations (57.4%). It was found in the clear-cell version of RCC. In cases of symptomatic RCC, expression of CA-IX was more frequently met (p < 0.05). There was a consistent association between the expression of CA-IX and the tumor size, stage and invasive potential. (For citation: Pasechnik DG, Kogan MI, Akhokhov ZM. The features of expression and prognostic significance of the peptide molecules connected with the key properties of renal cell carcinoma. Urologicheskie vedomosti. 2017;7(4):5-16. doi: 10.17816/uroved745-16).