Figure 6.

A–C: Immunohistochemical staining of MMTV/c-neu mammary carcinoma xenografts for CD31 revealing a multitude of tiny vessels in control tumors and fewer, but larger sinusoidal ones in the treated groups. D–F: Changes in the IMD; number of vessels per ×200 field of view) and vessel area density on days 5, 9, and 19 reflect a switch in the mode of angiogenesis: intussusception on day 9 and a second wave of sprouting on day 19. The values significantly different from control values are marked with *(P ≤ 0.02) or ^#(P ≤ 0.05). The HIF-1α staining (G–I) reveals the differences in oxygenation level of the tumor cells on day 14: in non-treated tumors (G) there is apparent hypoxia demonstrated by plentiful HIF-1α-positive cells on the distance of more than 100 to 130 μm from the vessels (arrowheads in G–I). There are necrotic areas on similar distances from the vessels (asterisks in G). On day 14 in both treated groups the level of oxygenation is apparently better with only some HIF-1α-positive cells (H and I). The vessels are marked with arrowheads (G–I). The magnification is ×200.