For successful therapy, hepatocellular carcinoma (HCC) must be detected at an early stage. Herein, we used a proteomic approach to analyze the secretory/releasing proteome of HCC tissues to identify plasma biomarkers. Serum-free conditioned media (CM) were collected from primary cultures of cancerous tissues and surrounding noncancerous tissues. Proteomic analysis of the CM proteins permitted the identification of 1365 proteins. The enriched molecular functions and biological processes of the CM proteins, such as hydrolase activity and catabolic processes, were consistent with the liver being the most important metabolic organ. Moreover, 19% of the proteins were characterized as extracellular or membrane-bound. For validation, secretory proteins involved in transforming growth factor-β signaling pathways were validated in plasma samples. Alphafetoprotein (AFP), metalloproteinase (MMP)1, osteopontin (OPN), and pregnancy-specific beta-1-glycoprotein (PSG)9 were significantly increased in HCC patients. The overall performance of MMP1 and OPN in the diagnosis of HCC remained greater than that of AFP. In addition, this study represents the first report of MMP1 as a biomarker with a higher sensitivity and specificity than AFP. Thus, this study provides a valuable resource of the HCC secretome with the potential to investigate serological biomarkers. MMP1 and OPN could be used as novel biomarkers for the early detection of HCC and to improve the sensitivity of biomarkers compared with AFP.
Biomarkers for hepatocellular carcinoma (HCC) following curative resection are not currently sufficient for prognostic indication of overall survival (OS) and disease-free survival (DFS). The aim of this study was to investigate the prognostic performance of osteopontin (OPN), matrix metalloproteinase 7 (MMP7), and pregnancy specific glycoprotein 9 (PSG9) in patients with HCC. A total of 179 prospective patients with HCC provided plasma before hepatectomy. Plasma OPN, MMP7, and PSG9 levels were determined by enzyme-linked immunosorbent assay. Correlations between plasma levels, clinical parameters, and outcomes (OS and DFS) were overall analyzed. High OPN (≥149.97 ng/mL), MMP7 (≥2.28 ng/mL), and PSG9 (≥45.59 ng/mL) were prognostic indicators of reduced OS (P<0.001, P<0.001, and P=0.007, respectively). Plasma PSG9 protein level was an independent factor in predicting OS (P=0.008) and DFS (P=0.038). Plasma OPN+MMP7+PSG9 elevation in combination was a prognostic factor for OS (P<0.001). OPN was demonstrated to be a risk factor-associated OS in stage I patients with HCC and patients with low α-fetoprotein levels (<20 ng/mL). These findings suggested that OPN, MMP7, PSG9 and their combined panels may be useful for aiding in tumor recurrence and mortality risk prediction of patients with HCC, particularly in the early stage of HCC carcinogenesis.
Hepatocellular carcinoma(HCC) is a common malignant solid tumor characterized by rich vascularization. Pregnancy-specific glycoprotein 9(PSG9) is a member of the carcinoembryonic antigen(CEA)/PSG family and is produced at high levels during pregnancy. We previously identified PSG9 as an HCC-related protein. However, the expression of PSG9 and its regulation during HCC carcinogenesis remain poorly explored. In the present study, we first found that the levels of PSG9 protein were significantly increased in the plasma of HCC patients. PSG9 overexpression also increased the proliferation ability of an HCC cell line. High expression of PSG9 was associated with angiogenesis by accelerating VEGFA expression. In addition, Cox's proportional hazards model analysis revealed that the plasma level of PSG9 was an independent prognostic factor for overall survival. We propose that PSG9 is a novel indicator of prognosis in patients with HCC and could serve as a novel therapeutic target for HCC. Furthermore,our results indicate that PSG9 protein may facilitate the development of HCC by fostering angiogenesis via promoting VEGFA production in cancer cells.
