Objective To investigate the role of microRNA-106a and microRNA-106b (miR-106a/b) in diagnosis and prognosis of hepatocellular carcinoma (HCC).Methods In this study,108 HCC patients and 54 age-and sex-matched healthy controls were enrolled.Blood samples were collected from each participant,and total RNA was extracted from the plasma.We determined miR-106a/b expression levels using quantitative reverse transcription polymerase chain reaction (qRT-PCR).Results The miR-106a/b expression levels in HCC patients were elevated compared with the healthy controls (P＜ 0.001).The ROC curve analysis showed that miR-106a/b expression levels could be used to predict the risk of HCC,with AUC values of 0.670 (95％ CI:0.573-0.768) and 0.684 (95％ CI:0.593-0.776),respectively.The miR-106a expression level in HCC patients correlated positively with hepatitis B surface antigen (HBsAg) presence (P =0.028),differentiation (P =0.025),tumor size (P =0.002),lymph node metastasis (P =0.028),and TNM stage (P =0.037).The miR-106b expression level correlated positively with HBsAg presence (P =0.003),alpha-fetoprotein (AFP) level (P =0.031),and tumor size (P =0.005).To further investigate the correlation of miR-106a/b expression levels with overall survival (OS),Kaplan-Meier curves were plotted.The results showed that HCC patients with high miR-106a expression displayed shorter OS (P =0.013).In addition,univariate and multivariate Cox proportional hazards regression showed that miR-106a was an independent risk factor for HCC prognosis.Conclusion Circulating miR-106a/b expression levels could be used as diagnostic biomarkers for HCC,and a high circulating miR-106a expression level is an independent risk factor for poor prognosis of HCC patients.