Figure 1

NG2 expression in mouse mammary tumor stroma. Sections of 16-week MMTV-PyMT mammary tumors were immunolabeled to demonstrate NG2 expression by elements of the tumor stroma. (A-D) Sections were labeled for CD31 (blue), desmin (green), and NG2 (red) to demonstrate the co-expression of desmin and NG2 by pericytes in close association with microvascular endothelial cells. D: high magnification of the boxed area in C. Arrowheads indicate pericytes expressing both desmin and NG2. (E-H) Sections were labeled for CD31 (blue), CD11b (green), and NG2 (red) to demonstrate the expression of NG2 by a subpopulation of CD11b-positive macrophages. H: high magnification of the boxed area in G. Arrowheads indicate macrophages positive for both CD11b and NG2. Arrow denotes blood vessel-associated CD11b-positive, NG2-positive macrophage. (I-L) Sections containing both normal and tumor tissue were labeled for CD31 (blue), desmin (green), and NG2 (red) to demonstrate the non-vascular expression of NG2 by adipocytes in the mammary fat pad. L: high magnification of the boxed area in K. Scale bars = 25 μm in D, H, and L. In all other panels, scale bars = 50 μm. MMTV-PyMT, mammary tumor virus-driven polyoma middle T; NG2, nerve-glial antigen 2.