Clinical significance of microRNA-155 expression in hepatocellular carcinoma

The present study aimed to evaluate the expression of microRNA-155 (miR-155) in hepatocellular carcinoma (HCC) and adjacent normal tissues, and assess its correlation with clinicopathological characteristics of this tumor type. miR-155 expression was detected in 40 HCC tissue samples and 40 samples of adjacent tumor-free tissue using fluorescent reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The association between miR155 expression, clinicopathological features and 1-year relapse-free survival (RFS) in HCC and adjacent normal tissue samples was analyzed. RT-qPCR results revealed that, in 25 cases (62.5%), miR-155 expression levels were significantly increased in HCC tissues compared with the expression levels observed in pericarcinomatous tissues (P<0.05). miR-155 expression was observed to be significantly correlated with vessel invasion, Edmonson classification and clinical stage (P<0.05). However, miR-155 expression was not significantly correlated with gender, age, tumor size, tumor number, hepatitis B virus DNA copy number, cirrhosis or concentration of a-fetoprotein (P>0.05). A positive correlation was observed between late TNM classification of malignant tumor stage and 1-year RFS (P<0.05). Patients exhibiting high miR-155 expression levels were observed to exhibit a lower 1-year RFS than that of patients with reduced expression of miR-155 (48 vs. 73.3%), however this difference was not statistically significant (P=0.105). Additionally, correlations were observed between miR-155 expression and reduced differentiation, increased invasiveness and late stages of HCC. The current results demonstrated that miR-155 may be involved in the tumorigenesis of HCC and may be associated with clinical characteristics of HCC patients. Additional studies are required to clarify the mechanism of miR-155.