Daizo YoshidaNippon Medical School, Japan
Title: Tumor Angiogenesis in Pituitary Adenoma
The role of angiogenesis in pituitary tumor development used to be questioned, since pituitary tumors have been usually found to be less vascularized than the normal pituitary tissue. Nevertheless, a significantly higher degree of vasculature has been shown in invasive or macropituitary prolactinomas when compared to nonin- vasive and microprolactinomas. We should know VEGF was found firstly in pituitary anterior lobe, then tumor angiogenesis must occur. Meanwhile the vascular arrange- ment raised by VEGF is irregular, that sometimes lead to pituitary apoplexy. In this chapter, hypoxia inducible factors (HIF), transcription factors regulating expression of several genes related to oxygen homeostasis are in response to hypoxic stress. We focus on tumor angiogenesis regulated by the signaling cascade in tumor angiogenesis in pituitary tumor.