Positive staining of type IV collagen, MMP9, MMP2, macrophages, and microvessels. A. BM was revealed by type IV Collagen staining. B. MMP9 was secreted by GC cells and mesenchymal. C. MMP2 expression is higher in malignant gland versus normal gland, especially nearby the BM. D. Macrophages are mainly located in the margin of the tumor nest, and phagocytosis of cancer cells by macrophage was observed (red arrow). E. New microvessels were increased at the tumor front. And CD105 is highly expressed on proliferating endothelial cells of both the peri- and intratumoral blood vessels (red arrow). Magnifications: A, B, C, D, E, F: 100×; Inserts in lower left corner show the sub-cellular localization of immunostaining at higher magnification (400×). All tissues were adenocarcinoma of GC.