Invasive growth and GBM properties of orthotopic DBM2 intracranial tumors. (A) Orthotopic DBM2 tumors exhibit extensive infiltration into the mouse brain parenchyma (a, b). The arrows point to areas of cranial erosion. (c) Higher magnification of DBM2 tumor demonstrating extensive infiltration into the brain parenchyma. Compared to DBM2, U251 tumors form a sharper cranial margin (d, e) and are less invasive (f). (B) Met (a, b) and uPAR (c, d) expression in invasive DMB2 orthotopic tumors. (C) H&E staining of formalin fixed DBM2 tumors shows central necrosis with the crowding of cancer cells lining the necrotic area (a, b arrows). Vascular invasion of DBM2 tumors along the perivascular space (arrow) and in vessels in the surrounding brain (c) with tumor-thrombus formation (d). Higher magnification showing a glomeruloid body-like structure (d, insert). CD31 staining highlights vascular proliferation (e). Enlargement of (e) showing glomeruloid body-like structure with multiple layers of endothelial cells is stained by CD31 antibody (f).