The F ‐prostaglandin receptor is a novel marker for tumor endothelial cells in renal cell carcinoma

Tumor angiogenesis is necessary for tumor progression and metastasis; therefore, tumor blood vessels are potential therapeutic targets in anticancer therapy. We previously reported that tumor endothelial cells ( TECs ) exhibit different phenotypes compared with normal endothelial cells ( NECs ), and microarray analyses of mouse TECs and NECs have shown that several genes are upregulated in TECs compared with NECs . Among these genes, the expression levels of prostaglandin F receptor ( PTGFR ) m RNA , which encodes the prostaglandin F receptor ( FP ), were higher in TECs than in NECs . It has been reported that FP and its ligand, prostaglandin F 2α , are involved in tumor angiogenesis. However, there have been no reports of the expression of PTGFR in the tumor vessels of renal cell carcinoma ( RCC ). Thus, we isolated human TECs (h TEC s) from RCCs . The expression levels of PTGFR m RNA were also upregulated in h TEC s. In addition, immunostaining showed that the PTGFR was expressed in human tumor blood vessels in vivo . These findings suggested that PTGFR is a novel TEC marker and that it may be a novel target for antiangiogenic therapy for RCC .