Clinicopathological investigation of vascular endothelial growth factor and von Hippel-Lindau gene-related protein expression in immunohistochemically negative pituitary adenoma--possible involvement in tumor aggressiveness.

Clinicopathological investigation of vascular endothelial growth factor and von Hippel-Lindau gene-related protein expression in immunohistochemically negative pituitary adenoma--possible involvement in tumor aggressiveness.