Exosomal microRNA‐4661‐5p–based serum panel as a potential diagnostic biomarker for early‐stage hepatocellular carcinoma

Currently, a reliable serum biomarker for hepatocellular carcinoma (HCC) has not been established, particularly for early‐stage HCC (single tumor < 2 cm). We aimed to investigate diagnostic serum exosomal microRNA (exo‐miR) panel for early‐stage HCC. Driver oncogenic miR (onco‐miR) candidates were selected by integrative analysis of miR expression profiles from three different RNA sequencing datasets of human HCC. Expressions of selected onco‐miRs in serum exosome were measured using quantitative real‐time PCR. Diagnostic performances of serum exo‐miRs for HCC were evaluated in the test cohort (N = 24) and validation cohort (N = 144). Serum exo‐miR panels were developed using a logistic regression model, and their diagnostic performance was evaluated. Six promising driver onco‐miRs, including miR‐25‐3p, miR‐140‐3p, miR‐423‐3p, miR‐1269a, miR‐4661‐5p, and miR‐4746‐5p, were identified by integrative analysis of three different RNA sequencing datasets. Among the six candidates, four serum exo‐miRs (miR‐25‐3p, miR‐1269a, miR‐4661‐5p, and miR‐4746‐5p) showed promising performance in the test cohort with area under the receiving operator curve (AUROC) >0.8. In our validation study, serum exo‐miR‐4661‐5p could diagnose HCC in all stages (AUROC = 0.917), even in early stage (AUROC = 0.923), with a greater accuracy than other candidate serum exo‐miRs and serum AFP. The panel composed of exo‐miR‐4661‐5p and exo‐miR‐4746‐5p was identified as the most accurate biomarker for early‐stage HCC (AUROC = 0.947, 95% confidence interval = 0.889‐0.980, sensitivity = 81.8%, and specificity = 91.7%). In conclusion, exo‐miR‐4661‐5p–based serum panel is a promising diagnostic marker for early‐stage HCC.