BMP7 and astrocytic tumor: To identify the exact role of BMP7 and its downstream Smad5 signaling in glioma development, a commercial brain tumor tissue microarray (GL807, US Biomax Inc., Rockville, MD, USA), which included thirty-three astrocytic tumor tissues and five healthy brain tissues, was used and an immunohistochemical stain was performed using the BMP7- and pSmad5-speific antibodies.