Abstract 1799: MicroRNA hsa-miR-26a expression in hepatocellular carcinoma correlates with patient survival

Abstract Background: MicroRNAs (miRNAs) are small noncoding RNAs that act as important regulators of gene expression at a post-transcriptional level. Using a next-generation sequencer system, in a previous study, we have identified 49 miRNAs expressed differentially by comparing 26 pair samples of hepatocellular carcinoma (HCC) tumor tissue and nontumor liver tissue. For this validation study, we selected hsa-miR-26a, one of the candidate miRNAs. We measured hsa-miR-26a expression in the validation set HCC samples using real-time quantitative polymerase chain reaction (qPCR) and examined the correlation between miRNA expression and clinical data. Patients and Methods: Overall, 40 patients with HCC who underwent tumor resection from 1991 to 1997 at the Department of Surgery, Institute of Gastroenterology, Tokyo Women’s Medical University, Japan were enrolled. Formalin-fixed paraffin-embedded samples were prepared using the standard protocol. The paraffin blocks were cut into 10-μm sections; HCC tumor and adjacent nontumor liver tissues were collected using laser-captured microdissection, and total RNA, including miRNA fractions, were isolated. Following the synthesis of a complementary DNA (cDNA) using an miRNA-specific primer, real-time qPCR was performed using an miRNA-specific primer/probe. Results: The hsa-miR-26a expression tended to be downregulated in HCC tumor tissue compared to nontumor liver tissue (P = 0.0799). Patients in the higher hsa-miR-26a expression group showed a significantly longer overall survival time compared with those in the lower hsa-miR-26a expression group (P = 0.0409). Conclusion: Inhibition of hsa-miR-26a expression might play a role in tumorigenesis, and hsa-miR-26a expression could be a potential prognostic factor for patients with HCC. Citation Format: Go Nakajima, Kazuhiko Hayashi. MicroRNA hsa-miR-26a expression in hepatocellular carcinoma correlates with patient survival [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1799.