miR-9-5p expression is associated with vascular invasion and prognosis in hepatocellular carcinoma, and in vitro verification.

Purpose: Hepatocellular carcinoma (HCC) is a common liver malignancy. Early vascular invasion (VI) has been associated with poor prognosis in HCC patients. MicroRNAs (miRNAs) play a significant role in the emergence and development of many tumor types.

Methods: Differential expression analysis of miRNAs related to VI was performed based on data from the TCGA database, and survival-associated miRNAs identified. We identified miR-9-5p as a survival-related miRNA and verified its expression in 61 clinical samples using quantitative real-time PCR. We further performed functional enrichment analysis, protein-protein interaction analysis, univariate and multivariate analysis of the survival-related miRNAs, and cell function assays.

Results: In this study, we identified miR-9-5p that could predict VI and prognosis in HCC patients. Cellular experiments demonstrated that downregulation of miR‑9‑5p inhibits migration, invasion, and angiogenesis of HCC cells. Further, we explored and verified the possible mechanism through which miR-9-5p is involved in HCC progression. Univariate and multivariate analysis revealed that miR-9-5p was an independent risk factor for HCC. Finally, the nomogram based on miR-9-5p showed a good predictive value of HCC survival.

Conclusions: MiR-9-5p is associated with VI in HCC, and higher expression of miR-9-5p indicates poor prognosis in HCC.