Monoacylglycerol lipase high expression as an independent indicator of survival for patients with hepatocellular carcinoma

Abstract

Objective: To study the expression level of monoacylglycerol lipase (MAGL) in liver tissues of patients with hepatocellular carcinoma (HCC), and its clinical correlation. Methods: Immunohistochemistry was employed to detect MAGL protein in 353 cases with hepatocellular carcinoma (HCC) and tissue microarray (TMA) for paracancerous liver tissues. The expression levels of MAGL in TMA were quantitatively analyzed using Image-Pro plus 6.0. The difference in MAGL expression between liver cancer tissues and paracancerous liver tissues was compared. Combined with the clinical follow-up data of TMA patients, the correlation between the expression of MAGL in TMA and the degree of HCC tumors differentiation and the survival rate of 1-year and 3-year were analyzed using Logistic regression analysis. The survival curves of patients with different levels of MAGL protein was plotted and analyzed using Kaplan-Meier method. The expression of MAGL protein was analyzed by multiple linear regression analysis. COX regression was used to analyze the correlation between MAGL protein expression level and the risk of HCC death in the included patients. Results: The expression of MAGL in HCC tissues was significantly higher than paracancerous liver tissues. The expression level of MAGL was correlated to the degrees of HCC tumors differentiation (P < 0.001) and 1-year survival rate (P = 0.01), but not with 3-year survival rate (P = 0.91). Survival curve showed that the expression level of MAGL was negatively correlated with prognosis and survival of HCC patients (P = 0.001). Multiple linear regressions showed a negative correlation between MAGL expression level and overall survival time of HCC patients (P=0.010, R2=0.166, Durbin-Watson value: 1.989). COX regression showed that the expression of MAGL was a risk factor for death of patients with HCC [P = 0.004, Exp (B) = 1.000]. Conclusion: The expression level of MAGL has positive correlation with the malignant degree in HCC patients, and negative correlation with its prognosis. Therefore, MAGL may serve as a new prognostic indicator for HCC patients.