Extracellular matrix protein 1, a novel prognostic factor, is associated with metastatic potential of hepatocellular carcinoma.

Extracellular matrix protein 1 (ECM1) is a glycoprotein involved in a number of biologic processes. To investigate the expression of ECM1 in hepatocellular carcinoma (HCC) and determine its correlation with tumor progression and prognosis, the expression levels of ECM1 in three HCC and one normal liver cell lines, tumor, and corresponding adjacent tissues from 18 HCC patients were analyzed by reverse transcription polymerase chain reaction (RT-PCR) and Western blotting. Immunohistochemistry assay was used to determine the expression of ECM1 in HCC and corresponding paracarcinomatous tissues from 77 patients. 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). Immunohistochemically, the expression of ECM1 in HCC was judged to be positive in 57 (74.0%) cases, significantly higher than that in corresponding paracarcinomatous tissues (P < 0.01), and it was associated with tumor size (P = 0.036), number of tumor nodules (P = 0.048), TNM stage (P = 0.029), and vascular invasion (P = 0.007). In particular, the expression of ECM1 was found to be an independent factor for predicting overall and disease-free survival of HCC. The expression level of ECM1 was associated with metastatic potential of HCC, and its abnormal expression may be used as a predictive factor of unfavorable prognosis and recurrence for HCC after surgery.