Predictive significance of tumor-associated miRNA-21 and -221 expression in patients with prostate cancer.

e17015 Background: It is thought that the occurrence and progression of tumors, such as prostate cancer (PCа), may be due to decreased levels of tumor-inhibiting microRNAs and/or overexpression of oncogenic microRNAs, but their specificity and role in tumor progression are contradictory. That is why the study of the possibility of using miRNAs as prognostic markers is especially relevant. Objective: to investigate the features of tumor -associated microRNAs-21 and -221 expression in PCa tissue with different risk of progression and to determine the relationship of their indicators with the molecular profile of tumors. Methods: The study was conducted on the clinical material of 60 patients with PCa stage II-III, who were treated in Rivne Regional Hospital and Rivne oncological center during 2018-2021 years. Determination of the risk of PCa progression was performed by D'Amico et al. (1998). Immunohistochemical study of Ki-67 expression (clone MIB -1) and androgen receptors (AR) (clone 441) were performed on paraffin sections of tumor tissue using the Ultra Vision LP Detection System (Thermo Scientific, USA). Determination of microRNA-21 and -221 levels were determined using real-time quantitative PCR. Statistical processing of the results was performed using GraphPad Prism 8. Results: It is determined that a characteristic feature of PCa with a low risk of progression by D'Amico et al . are low expression of oncogenic miRNA-21 and -221 in tumor tissue. In particular, in the PCa samples of high risk of progression (n = 30) the level of miRNA-21 was 3.2 times (p < 0.05), and miRNA-221 was 1.35 times (p < 0.05) higher compared to tumor tissue of patients with low progression (n = 30). The existence of a direct correlation between the expression of miRNA-21 and the proliferative activity of PCa (ρ = 0.63; p < 0.05) is shown. We found that the expression of miRNA-221 is associated with a high level of AR expression (ρ = 0.43; p < 0.05) . Conclusions: The obtained data indicate the relationship of tumor -associated microRNA-21 and -221 with the risk of tumor progression and such molecular biological characteristics of tumors as proliferative activity and receptor status, which indicates the prospects for their further study as additional markers for predicting of PCa course.