Expression of miR-221 and miR-18a in patients with hepatocellular carcinoma and its clinical significance.

Purpose: Recently, microRNA (miRNA) has been evaluated to provide a new diagnostic and therapeutic modality hepatocellular carcinoma (HCC) and other tumors. They are small non-coding RNA molecules that function as transcriptional and post-transcriptional regulators of gene expression by silencing target genes. The aim of this study was to evaluate the clinical significance of microRNA-18a, 221 (miR-18a, miR-221) expression in HCC formalin-fixed paraffin-embedded (FFPE) tissue.

Methods: miR-18a and miR-221 expressions were assessed by reverse transcription and real-time quantitative reverse transcription polymerase chain reaction in 50 pairs of FFPE HCC and the adjacent noncancerous liver tissues. And we evaluated the expression level in HCC tissues as compared with their adjacent noncancerous counterparts. And the relationship between miR-18a, miR-221 level and clinicopathological data and survival rates were analyzed.

Results: miR-221 and miR-18a were overexpressed in HCC tissue as compared with their adjacent noncancerous liver tissue (P<0.001). miR-221 expression was found to be correlated with larger tumor size (P=0.048). miR-18a expression was correlated with modified Union for International Cancer Control stage (P=0.05). The overall survival (P=0.02) of HCC patients with high miR-221 expression was significantly poorer compared to those patients with low expression. Multivariate analyses demonstrated that miR-221 may be a poor prognostic factor of HCC patients.

Conclusion: High expression of miR-221 in FFPE tissues could provide significance for prognosis of HCC patients. Although, miR-18a expression was significantly upregulated in HCC tissues, they are not correlated with prognosis. Further large prospective studies are needed to determine their clinical significance.