ESPRESSIONE'DEI'MICRORNA'MIR221'E'MIR222' NEL'CARCINOMA'EPATOCELLULARE' SIGNIFICATO'CLINICO'E'PROGNOSTICO

Background: Hepatocellular carcinoma (HCC) is a primary cancer of the liver with high incidence and mortality. It is managed with a multidisciplinary approach depending on the stage of disease with a combination of surgical resection, liver transplant, loco-regional therapies and chemotherapy. Several diagnostic and prognostic tools have been investigated to improve outcomes, including biological marker, radiological and histopathological features, but at present there is no univocal consensus on their efficacy. In the era of genomics and molecular medicine, the role of microRNAs is being studied in HCC with the aim to identify a signature of specific microRNAs selectively expressed in HCC to use as diagnostic and prognostic markers as well as possible therapeutic targets. MicroRNA miR-221 and miR-222 may be upregulated in over 80% of HCCs. The aim of this study was to assess miR-221 and miR-222 expression in paired hepatic tumoral and non-tumoral tissues of patients undergoing liver resection for HCC. Primary outcome was the presence of significant upregulation in the tumoral tissue compared to the matched non-tumoral tissue. Secondary outcomes were the correlation of miR-221 and miR-222 expression with clinical variables and survival. Methods: Eligible patients undergoing liver resection for HCC at National Cancer Institute (Milan) were prospectively included in the study. Paired tumoral and non-tumoral hepatic tissues were sampled intraoperatively, fresh-frozen and analyzed for miR-221 and miR-222 expression. Clinical, pathological and survival data were prospectively recorded. Upregulation was deemed significant with a tumoral/non-tumoral ratio >1. Kaplan-Meier curves were used to assess survival. Prognostic efficacy of miR-222 ratio was evaluated by receiver operating curve (ROC) analysis. Results: Between January 2012 and September 2015, 56 patients were enrolled. Six patients were BCLC 0, 35 BCLC A, 12 BCLC B and 3 BCLC C. MiR-221 and miR-222 were upregulated in 59% and 52% of cases, respectively. Upregulation was significantly correlated with a more advanced grade of differentiation (p=0.0012) whilst there was no correlation with AFP, microvascular invasion, BCLC stage and number of nodules. At univariate analysis, age, male gender, miR-221 and miR-222 ratios were associated with worse recurrence free survival (RFS). Independent predictors of worse RFS at multivariable analysis were male gender and miR-222 ratio. ROC analysis showed that miR-222 had a good performance in predicting the risk of recurrence at two years from resection (area under the curve 0.74; 95% CI 0.57 – 0.87; p=0.005) with an optimal cut-off of > 1.16 (Youden index J = 0.61). Median RFS for patients with miR-222 ratio ≤1.16 and >1.16 were 45.7 versus 12.3 months (p=0.0003). This difference was confirmed also in a subgroup analysis according to BCLC stage. Conclusions: In our series, miR-221 and miR-222 were upregulated in more than half of patients undergoing liver resection for HCC. Independently from the BCLC stage, patients showing upregulation had a significantly worse RFS. A miR-222 ratio >1.16 was the optimal cut-off to predict an increased risk of recurrence at two years from resection. This may be of use as a prognostic marker for HCC and further studies on a larger scale are needed to confirm its efficacy.