Overexpression of EphA4 gene and reduced expression of EphB2 gene correlates with liver metastasis in colorectal cancer

The Eph receptors, members of a large family of transmembrane receptor tyrosine kinases, play important roles in a variety of biological functions. Recent studies have suggested that EphA4 and EphB2 participate in the growth and development of various carcinomas. This study examined the relationship of EphA4 and EphB2 gene expression to clinicopathological factors, especially metastasis, in patients with colorectal cancer. We studied surgical specimens of cancer tissue and adjacent normal mucosa obtained from 205 patients with untreated colorectal cancer. The relative expression levels of EphA4 and EphB2 mRNA in the specimens were measured by quantitative real-time, reverse-transcription polymerase chain reaction. The relative expression level of EphA4 mRNA was higher in the presence than in the absence of liver metastasis, whereas the relative expression levels of EphB2 mRNA were similar. Analysis of the relationship between clinicopathological features and gene expression showed that high expression of the EphA4 gene and low expression of the EphB2 gene correlated with liver metastasis. There was no correlation between EphA4 and EphB2 gene expression. Our results suggest that overexpression of the EphA4 gene and reduced expression of the EphB2 gene might promote liver metastasis in colorectal cancer. Overexpression of the EphA4 gene and reduced expression of the EphB2 gene may thus be a useful predictor of liver metastasis in patients with colorectal cancer.