To analyze the expression level and clinical significance of syntaxin 6 (STX6) in hepatocellular carcinoma (HCC) based on bioinformatics database.

The expression of STX6 gene in the healthy human tissues was analyzed by BioGPS database. The expression of STX6 in common tumors was assessed by Oncomine database. The expression profile of STX6 gene in HCC was determined by Meta-analysis. The effect of STX6 expression on the overall survival (OS) and progression-free survival (PFS) of HCC patients was evaluated in Kaplan-Meier plotter database. The proteins interacting with STX6 were identified in String database.

STX6 gene was found expressed in all normal human tissues including liver tissues, with high expression levels in the whole blood, NK cells and myeloid cells. From 2002 till now, 16 studies involving statistical significances in the STX6 expression have been identified, including 13 studies of up-regulated STX6 expression and 3 of down-regulated STX6 expression. 8 gene chip studies demonstrated that the expression level of STX6 in HCC tissues was significantly higher than that in normal liver tissues (Fold change=1.510, 1.094, 1.103, 1.124, 1.716, 1.844, 1.269, 2.484; P<0.05). Meta-analysis of the 8 studies showed that STX6 expression was up-regulated in HCC tissues (Median rank=569, P<0.05). The OS and PFS in STX6 high expression group were significantly lower than those in STX6 low expression group (HR=1.91, 1.62; P<0.05). Analysis of protein interaction network revealed that proteins, such as VAMP4, VAMP8, VAMP3, NAPA, VPS51, STX16, STX12, STX5, SNAP23 and VTI1A, significantly interacted with STX6. A majority of proteins participated in physiological functions such as vesicle transportation in and out of cells or between organelles.

The findings based on the analysis of tumor gene database demonstrate that STX6 is highly expressed in HCC tissue, STX6 expression is correlated with the prognosis of HCC patients, and the prognosis of patients with high expression of STX6 is poor.