Background: Liver metastasis of gastric cancer (GC) is highly associated with poor prognosis. The development of sensitive biomarkers for detecting and predicting liver metastasis is required for better clinical outcome.
Objective: In this study, we aimed to identify novel genes associated with liver metastasis of GC.
Methods: Global expression profiling of 57,749 genes was performed using surgically resected gastric tissues from four patients with liver metastasis to identify candidate genes. The mRNA expression levels of the selected candidate gene were analyzed in the resected gastric tissues of 300 GC patients and correlated with clinicopathological parameters. Fourteen GC cell lines were subjected to mRNA expression and polymerase chain reaction (PCR) array analysis.
Results: Among 25 candidate genes identified by transcriptome analysis, preferentially expressed antigen of melanoma (PRAME) was selected for subsequent analyses. mRNA expression analysis of clinical samples revealed the aberrant expression of PRAME in GC tissues, and its high expression was significantly related to differentiated phenotype and vessel invasion, as well as liver metastasis. High PRAME expression was significantly associated with hepatic recurrence after curative surgery, and cumulative incidences of hepatic recurrence were significantly greater in patients with high PRAME expression compared with patients with low PRAME expression. In an in vitro analysis, overexpression was observed in all GC cell lines compared with a normal epithelial cell line. PCR array analysis revealed the coordinate expression of MMP9, OCLN, IL1RN, and MST1R.
Conclusions: PRAME is related to the malignant potential of GC and could serve as a novel biomarker for the detection and prediction of liver metastasis.