Expression of chemokine receptors in human gastric cancer

Abstract

The roles of chemokine receptors in cancer metastatic processes continue to draw research attention. Here we evaluated the expression profiles of the chemokine receptors CCR7 and CXCR4 in gastric cancer, and their potential use as prognostic markers. The expressions of CCR7 and CXCR4 mRNA were analyzed by RT-PCR in 10 human gastric cancer cell lines and in 43 gastric cancer tissues, and in an additional 307 gastric cancer tissues by immunohistochemistry. Clinicopathological features and the prognoses of patients were also evaluated versus the expression of these two cytokine receptors. CCR7 and CXCR4 mRNA were found to be expressed in all gastric cancer cell lines, whereas their mRNA expression rates in gastric cancer tissues were 83.7% (36/43) and 100% (43/43), respectively. Immunohistochemical staining of the 307 gastric cancer tissues showed that the expression rates of CCR7 and CXCR4 were 22.5% (69/307) and 36.5% (112/307), respectively. Multivariate analysis of the immunohistochemistry results showed that the expression rate of CCR7 was significantly higher in differentiated than in undifferentiated gastric cancertypes (35.1 vs. 15.3%, p<0.001), and that CXCR4 was expressed at a higher rate in intestinal cancer than in diffuse-type cancer (58.8 vs. 22.3%, p<0.001). However, in contrast to previous studies, the expressions of CCR7 or CXCR4 were not associated with lymph node metastasis. Moreover, the prognosis of patients with CCR7-positive tumors was better than that of patients with CCR7-negative tumors, but no such correlation was observed for CXCR4 expression. In conclusion, the expressions of the chemokine receptors CCR7 and CXCR4 were found to be high in differentiated and intestinal-type gastric cancers, respectively.