Identification of signature genes for detecting hedgehog pathway activation in esophageal cancer

The hedgehog signaling pathway plays an important role in cell growth and differentiation both in normal embryonic development and in tumors. Our previous work shows that hedgehog pathway is frequently activated in esophageal cancers. To further elucidate the role of hedgehog pathway in esophageal cancers we examined the expression of the target genes, hedgehog-interacting protein (HIP) and platelet derived growth factor receptor alpha (PDGFRα) and hedgehog signaling molecules, smoothened (SMO), suppressor of fused (Su(Fu)) in the specimens using in-situ hybridization and RT-PCR. We found that HIP, PDGFRα, SMO and Su(Fu) gene highly expressed in the primary esophageal squamous cell carcinomas but not in normal esophageal tissue. The transcripts of HIP, PDGFRα and SMO were expressed in 13 of 15 esophageal cancers. Su(Fu) expression was missing in 2 esophageal cancers. The results from in-situ hybridization were further confirmed by RT-PCR. Our results revealed a set of genes for detecting hedgehog signaling activation in esophageal cancer.