Expression And Clinical Significance Of Extracellular Matrix Protein 1 In Hepatocellular Carcinoma

【Objective】Evaluate extracellular matrix protein 1 (ECM1) expression in hepatocellular carcinoma (HCC), corresponding adjacent tissues, and normal liver tissues, and three HCC cell lines with various metastatic potentials by reverse transcriptase polymerase chain reaction (RT-PCR) and Western blotting, and to determine the relationship between the expression level and HCC metastatic potential. In addition, it is also to evaluate the ECM1 expression in a hospital-based cohort of patients with HCC by immunohistochemistry and enzyme-linked immunosorbent assay (ELISA), and to elucidate the expression of ECM1 in HCC and its association with clinicopathological characteristics and prognosis, including exploring the biological function and mechanism of ECM1 in the process of metastasis and recurrence, and objectively assess the prognosis of HCC.【Methods】(1) RT-PCR and Western blotting was used to evaluate ECM1 expression in HCC, corresponding adjacent tissues, and normal liver tissues, and three HCC cell lines with various metastatic potentials, and to determine the relationship between the expression level and HCC metastatic potential. (2) The preoperative serum ECM1 levels in a hospital-based cohort of patients with HCC by ELISA to elucidate the serum levels of ECM1 in HCC and its association with clinicopathological characteristics and prognosis. (3) In addition, it is also to evaluate the ECM1 and matrix metalloproteinase 9 (MMP-9) expressions in a hospital-based cohort of patients with HCC by immunohistochemistry, and to elucidate the expression of ECM1 and MMP-9 in HCC and them correlation and association with clinicopathological characteristics and prognosis.【Results】(1) The results of Western blotting were consistent with the results from RT-PCR analysis of ECM1 mRNA expression. Among the four cell lines, the expression level in HCCLM3, which with the highest metastatic potential, was significantly higher than that with lower (P<0.05); while ECM1 expression was not detected in normal liver cell line. Expression level of ECM1 was significantly increased in HCC compared with adjacent and normal liver tissues (P<0.05), they was no significance between adjacent and normal liver tissues. (2) ECM1 was detected in all the samples of 117 HCC patients and 53 healthy volunteers. The median serum ECM1 level in HCC patients was significantly higher than that in healthy volunteers (166.39 vs 108.06 pg/ml, P<0.001). Median serum ECM1 levels were significantly higher in patients with invasive phenotypes, such as advanced TNM stage (P<0.001), multiple nodule (P=0.028), vascular invasion (P<0.001), and larger tumor size (P=0.001). On Cox proportional-hazard model multivariate analysis, high serum ECM1 level (>180 pg/ml) was found to be an independent prognostic factor for overall survival and disease free survival of HCC patients. (3) Immunohistochemically, the expression of ECM1 and MMP-9 in HCC were mainly located in the cytoplasm, The positive rates of ECM1 and MMP-9 expression in HCC tissues were 73.3% (88/120) and 65.0% (78/120), significantly higher than that in normal liver tissues, respectively. The expression of ECM1 in HCC tissues was significantly correlated with vascular invasion and TNM stage. The expression of MMP-9 in HCC tissues was significantly correlated with tumor size, the number of tumor nodules, the differentiation of tumor and the stage of liver cirrhosis. None of them correlated with age, gender, serum AFP level, HBsAg, Child-Pugh class and tumor capsular, et al. The patients with both ECM1 and MMP-9 positive have significantly poorest overall and disease-free survival rate. In particular, the expression of ECM1 and MMP-9 were found to be independent factors for predicting overall and disease free survival of HCC. There was a significant positive correlation between ECM1 and MMP-9 (r=0.585, P<0.001).【Conclusions】The expression level of ECM1 was positively correlated with the malignant degree, and was the independent risk factor of overall and disease-free survival rate after operation of HCC. ECM1 level in HCC patients are significantly associated with invasive phenotypes, it may present a diagnostic marker for predicting the prognosis and recurrence of HCC patients after surgery, and may via correlated with MMP-9 to promote the invasion of HCC.