A rational approach for selection of miRNA-markers suitable for the development of prostate cancer diagnostics.

Olga Bryzgunova ^1,2 Ivan Zaporozhchenko ^1,2 Evgeniy Lekchnov ^1,2 Evgeniya Amelina ³ Maria Konoshenko ^1,2 Elena Rykova ^1,2 Sergey Yarmoschuk ⁴ Oxana Pashkovskaya ⁴ Anton Gorizkii ⁴ Svetlana Pak ⁵ Pavel Laktionov ^1,2

¹The Laboratory of Molecular Medicine, Institute of Chemical Biology and Fundamental Medicine, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
²The Laboratory of Biomedical Technologies, Meshalkin Siberian Federal Biomedical Research Center, Ministry of Public Health of the Russian Federation, Novosibirsk, Russia
³Department of Mathematical Modeling MMF, Federal State Autonomous Educational Institution of Higher Education "Novosibirsk National Research University", Novosibirsk, Russia
⁴Department of Oncology and Radiotherapy, Meshalkin Siberian Federal Biomedical Research Center, Ministry of Public Health of the Russian Federation
⁵The Department of Blood Transfusion, Meshalkin Siberian Federal Biomedical Research Center, Ministry of Public Health of the Russian Federation

Establishment of the adequate cut off value of circulating markers in a diagnostic system and subsequent data analysis for decision making are of a great importance. Accomplishing it is very costly as it requires an extensive study of large groups of patients and thus needs rational approaches to prevent waste of time and money. In this study, we offer rational approaches for selection of miRNA markers and their cut off levels to establish a diagnostic system for prostate cancer (PCa) based on the study of urine miRNAs.

The expression and distribution of 84 miRNAs in urine extracellular vesicles (EVs) and cell-free supernatant were studied in healthy donors (HD), patients with benign (BPH) and malignant prostate tumors (PCa) using miRCURY LNA miRNA qPCR Panels. Sets of miRNAs differentially expressed between the groups were found using ratio-based normalization. The cutoff value was set to mean + 2 standard deviation (SD) or mean - 2SD, as determined in the "HD + BPH" group. Patients with dCt/ddCt values outside of the cut off were considered to have PCa. miRNAs pairs having the lowest SD and maximum dCt/ddCt and differentially expressed in the most number of patients were chosen as best candidates. Overlapping between markers provides the system with reliability, while total coverage of cancer patients (high sensitivity) demands for inclusion of rarely encountered markers. Resulting panels comprised of 24 miRNA (17 analytical miRNA ratios) can be used to classify PCa and BPH patients and HD with 100% specificity and 97.5% accuracy. The diagnostic system based on the expression of 5 miRNA pairs (miR-30a: miR-125b, miR-425: miR-331, miR-29b: miR-21, miR-191: miR-200a, miR-331: miR-106b) can be potentially used to identify PCa.

The work was supported by the Russian Science Foundation (no. 16-15-00124).