Purpose: To evaluate the value of serum midkine (MDK) as a diagnostic biomarker in hepatocellular carcinoma, particularly for those with negative alpha-fetoprotein (AFP) and at an early stage.Experimental Design: MDK expression in tumors was assessed by immunohistochemistry from 105 patients with hepatocellular carcinomas or liver cirrhosis. Serum MDK levels were detected by ELISA in 933 participants including hepatocellular carcinomas and hospital controls from different medical centers. Sensitivities and specificities of serum MDK in diagnosing hepatocellular carcinoma according to AFP level and Barcelona Clinic Liver Cancer (BCLC) stage were analyzed.Results: MDK levels were significantly elevated in hepatocellular carcinoma tissues as well as serum samples. The sensitivity of serum MDK for hepatocellular carcinoma diagnosis was much higher than that of AFP (86.9% vs. 51.9%) with similar specificities (83.9% vs. 86.3%). Notably, serum MDK had an outstanding performance in distinguishing AFP-negative hepatocellular carcinomas from different controls: In those AFP-negative hepatocellular carcinomas, the sensitivity could reach as high as 89.2%. Moreover, receiver operating characteristic (ROC) curve analysis also showed that serum MDK had a better performance compared with AFP in distinguishing early-stage hepatocellular carcinomas as well as small hepatocellular carcinomas. Even in very early-stage hepatocellular carcinomas, MDK showed an obviously higher sensitivity compared with AFP (80% vs. 40%). Furthermore, serum MDK level was significantly decreased in patients with hepatocellular carcinomas after curative resection and re-elevated when tumor relapse occurred.Conclusions: Serum MDK is significantly elevated in most hepatocellular carcinomas, including those with negative AFP and at an early stage, which may serve as a novel diagnostic marker in early diagnosis and postoperative monitoring of hepatocellular carcinomas.

Esophageal cancer (EC) is a highly aggressive neoplasm with poor prognosis. The main reason for this disappointing outcome is the strong behavior of esophageal cancer cell's invasion and metastasis. CXC chemokine receptor 4 (CXCR4) was found to be expressed in many tumors and significantly correlated with invasion, angiogenesis, metastasis, and prognosis. In the present study, we investigated the expressions of CXCR4, matrix metalloproteinase-9 (MMP-9), and vascular endothelial growth factor (VEGF) in esophageal squamous cell cancer (ESCC) and analyzed the relationship among the three proteins. Sections of paraffin-embedded tissues were obtained from 127 patients with ESCC undergoing esophagectomy at Zhongshan Hospital, Fudan University in 2005. The CXCR4, MMP-9, and VEGF expressions in EC tissues were evaluated according to the immunohistochemical staining area and intensity. The correlations between patients' prognosis and covariates were analyzed by Kaplan--Meier method (univariate analysis) and Cox regression (multivariate analysis). The overall expression rate of CXCR4, MMP-9, and VEGF was 88.2%, 93.7%, and 79.5%, respectively. CXCR4 expression was significantly associated with tumor grade, tumor size, tumor depth, regional lymph node metastasis, and tumor, node, metastasis (TNM) stage (P < 0.05). MMP-9 expression was significantly associated with age and tumor grade (P < 0.05). VEGF expression was significantly associated with tumor grade, tumor depth, and TNM stage (P < 0.05). CXCR4 expression was positively correlated with MMP-9 expression (P < 0.01, r= 0.365) and VEGF expression (P < 0.01, r= 0.380). However, there was no significant correlation between MMP-9 and VEGF expression (P > 0.05). In univariate analysis, CXCR4 expression, tumor size, tumor depth, lymph node metastasis, and TNM stage were correlated with patients' prognosis (P < 0.05); in multivariate analysis, tumor size and lymph node metastasis were the independent factors of poor prognosis. CXCR4 was highly expressed in ESCC and correlated with MMP-9, VEGF, clinicopathological features and prognosis. We speculated CXCR4 play an important role during the progression of this disease and there might be some regulatory mechanism existing between CXCR4 and MMP-9/VEGF in ESCC.