Specific miRNA expression profiles of non‐tumor liver tissue predict a risk for recurrence of hepatocellular carcinoma

Aim It is reasonable to investigate non-tumor liver tissues to predict a risk for development of hepatocellular carcinoma (HCC). A molecular analysis of chronically damaged liver tissues may identify specific miRNA expression profiles associated with a risk for multicentric (MC) HCC. Methods Twenty HCC patients, who underwent a curative hepatectomy were classified into two groups: a non-MC group (no MC recurrence in more than 3 years, n = 10) and an MC group (MC recurrence within 3 years after hepatectomy, n = 10). An miRNA microarray (955 probes) was used to compare the miRNA expression patterns of the non-cancerous liver tissues between the two groups. This study identified the differentially expressed miRNA related to MC recurrence in the liver remnant. Results No differences were observed between the two groups in the liver function tests and pathological variables including both tumor factors and non-tumor liver tissues. The investigation selected 20 differentially expressed miRNA related to MC recurrence. Eighteen miRNA were downregulated, while two miRNA were upregulated in the MC group. A hierarchical clustering analysis identified a cluster that may be associated with risk of the MC recurrence of HCC. The MC recurrence-related miRNA included let-7d*, miR-328 and miR18a*, which potentially regulate K-ras gene expression. A significant inverse correlation between the miR-18a* expression and the K-ras mRNA expression was confirmed by quantitative reverse transcription polymerase chain reaction. Conclusion Specific miRNA expression signatures in non-cancerous liver tissue may help to predict the risk for de novo development of HCC.