To detect the expression of microRNA (miRNA, miR)-21 in hepatocellular carcinoma (HCC) tissue samples and to explore its association with clinicopathologic features.

The real-time quantitative reverse transcriptase-polymerase chain reaction (RT-qPCR) analysis was used to detect the expression of miR-21 in tissue specimens from HCC and the adjacent non-cancerous hepatic tissues collected from 81 patients who underwent surgical treatment for primary HCC and in normal liver tissues collected from 20 patients. Statistically, the association between the expression of miR-21 and clinicpathologic characteristics and prognosis of patients was analyzed.

The expression of miR-21 was up-regulated in HCC [(6.34±0.23) fold, P=0.003] and the adjacent non-cancerous hepatic tissues [(3.44±0.12) fold, P=0.020] as compared with that in the normal liver tissues. The results showed that high expression of miR-21 was strongly correlated with the characteristics of tumor size (χ²=11.034, P=0.001), metastasis (χ²=12.081, P=0.001), venous invasion (χ²=13.372, P=0.000) and American Joint Committee on cancer (AJCC) TNM stage (χ²=12.175, P=0.000). There were no significant associations between miR-21 expression and gender (χ²=0.290, P=0.590), age (χ²=0.036, P=0.850), tumor location(χ²=0.593, P=0.441), tumor grade (χ²=2.729, P=0.099), tumor number (χ²=1.597, P=0.206) and alpha fetal protein (AFP, χ²=0.279, P=0.597). Patients with high miR-21 expression had significantly poorer overall survival (27.2% vs. 10.7%, P=0.003). High miR-21 expression was independent prognostic factors for overall survival (P=0.001).

The expression of miR-21 is highly up-regulated in HCC tissues, which is correlated significantly with the process of metastasis and unfavorable prognosis.

Carcinoma, hepatocellular; MicroRNA-21; Clinical significance