Mir-29a is a candidate biomarker of better survival in metastatic high-grade serous carcinoma

Summary The objective of this study was to analyze the clinical role of 9 microRNAs (miRs) previously found to be overexpressed in ovarian carcinoma effusions compared with primary ovarian carcinomas. High-grade serous carcinoma effusions (n = 148) were analyzed for expression of miR-29a, miR-31, miR-99b, miR-182, miR-210, miR-221, miR-222, miR-224, and miR-342 using quantitative polymerase chain reaction. Expression levels were analyzed for association with clinicopathological parameters and survival. miR-29a and miR-31 levels were further assessed for association with protein expression of their targets Stathmin and DNA methyltransferase-3A (DNMT3A) by immunohistochemistry and Western blotting, respectively. miRNA levels were unrelated to clinicopathological parameters. However, higher miR-29a levels were significantly related to longer overall survival in univariate ( P  = .007) and Cox multivariate survival analysis ( P  = .045). miR-29a levels were inversely related to those of its target DNMT3A ( P  = .048), and higher DNMT3A expression was significantly related to poor overall survival in univariate ( P  = .03) and Cox multivariate ( P  = .016) survival analysis. In contrast, miR-31 levels were directly related to cytoplasmic phospho-Stathmin expression ( P  = .029) and unrelated to Stathmin and nuclear phospho-Stathmin, and both Stathmin and phospho-Stathmin expressions were unrelated to survival. miR-29a and its target DNMT3A are novel candidate biomarkers of longer and shorter survival, respectively, in metastatic high-grade serous carcinoma.