An immunohistochemical study of neovasculature in human brain tumors.

In order to elucidate the characteristics of newly-formed small blood vessels in brain tumors, 51 cases of various types of brain tumor were studied immunohistochemically. Endothelial cells in all tumor types reacted positively with anti-Factor VIII-related antigen (F-VIII Ag) and UEA-1. Reactivity to UEA-1 was limited to endothelial cytoplasm. Proliferating immature endothelial cells showed weak reactivity to anti-F-VIII Ag. In some cases of benign tumors diffuse reactivity to anti-F-VIII Ag was noted throughout thickened medial areas of the vascular walls, in which reactivity to anti-fibrous collagen and anti-fibronectin was noted. UEA-1 was thought to be a more specific endothelial marker than F-VIII Ag, especially for proliferating and immature endothelial cells. It is strongly suspected that fibrous collagens are related to the formation of a thickened vascular wall in newly-formed small tumor vessels.