Downregulation of MicroRNA-122 (miR-122) and its association with cancer progression have been reported in hepatocellular carcinoma (HCC) cell line models and a limited number of HCC samples. Recently, restoration of miR-122 expression by direct delivery of miR-122 yielded promising results in HCCs. However, the prognostic effect of miR-122 expression in human HCC samples is not fully understood. We investigated the expression level of miR-122 by quantitative real-time polymerase chain reaction in 289 curatively resected HCC samples and 20 normal liver samples and evaluated the prognostic effect of miR-122 expression. The relative quantification value of miR-122 was much lower in HCC samples than in normal liver tissues. During a median 119 months of follow-up for survival, the low miR-122 expression group showed shorter recurrence-free survival (RFS) (p = 0.033) and intrahepatic recurrence-free survival (IHRFS) (p = 0.014), and a trend of short distant metastasis-free survival (DMFS) (p = 0.149) than high expression group. On multivariate analysis, miR-122 expression was an independent prognostic factor for RFS, IHRFS and DMFS. Downregulation of miR-122 expression, frequently found in HCC samples, was an independent prognostic factor for RFS after curative resection. Emerging therapeutic approaches targeting miR-122 could be applicable in patients with miR-122 downregulated hepatocellular carcinoma.

Although several studies have confirmed the clinical significance of the systemic inflammation markers in hepatocellular carcinoma (HCC), evaluating the clinical significance of each blood cell remains to be conducted. We aimed to evaluate the clinical importance of absolute counts of blood cells in the overall survival (OS) of patients with newly diagnosed HCC. We recruited patient cohorts from the prospective registry of newly diagnosed and previously untreated HCC at Samsung Medical Center, which included a training set of 6619 patients (2005-2013) and a validation set of 2084 patients (2014-2016). More than three-quarters of all patients had hepatitis B virus (HBV)-related HCC in both training and validation sets. The optimal cutoff values of the absolute counts of neutrophils, lymphocytes, monocytes, and platelets were 3917, 488, 1379, and 22,100, respectively, which correlated significantly with OS. The absolute blood cell counts categorized by each optimal cutoff value significantly correlated with liver function status determined by Child-Pugh class/albumin-bilirubin (ALBI) grade and the HCC burden determined by several staging systems/portal vein tumor thrombosis. Although the prognostic model based on these blood cells (ABC model) showed a lower prognostic ability than the Japan Integrated Staging or ALBI-T staging systems, it provided significant discrimination of survival in the subgroups of ALBI-T and showed the highest prognostic ability in the present study in the training and validation sets. Absolute counts of blood cells are independently associated with OS, though it is also significantly associated with liver function and tumor burden in newly diagnosed HCC.