Figure 3

Histological analyses of tumors produced by transformed MCF10A cells in nude mice. The first row from the top shows neovascularity in the peritumoral stroma of a large tumor formed by transformed MCF10A cells in nude mice.A. Positive immunoreactivity with anti-CD31 antibody (DAB chromagen) from tumors formed in nude mice by MCF10AβL cells selected for hypoxia resistance. B. Negative staining with a control IgG antibody. The second and third rows from the top show variable degrees of tumor differentiation by transformed MCF10A cells. C. H&E section of MCF10AαL tumor cells, which were selected for reduced growth factor supply shows focal clear cell change (*) with adjacent prominent ductal differentiation (see arrows). D. H&E section of a tumor formed in a nude mouse by MCF10AαL cells selected for hypoxia resistance exhibit growth within desmoplastic stroma with central comedo-like tumor necrosis. E. H&E section of a tumor formed by the secondary inoculation of MCF10AαL cells selected for reduced growth factor supply shows an area of geographic necrosis (*) with adjacent clear cell change (arrow) and nested growth of pleomorphic cells. F. H&E section of another tumor formed by secondary inoculation of MCF10AαL cells selected for reduced growth factor supply shows nested and strand-like growth of cells (*) within a desmoplastic stroma (arrows). The last row from the top shows the invasiveness of tumors formed by transformed MCF10A cells. G. H&E section of a tumor formed by MCF10AαL shows that the tumor (*) begins to infiltrate into the adjacent skeletal muscle (arrow). H. H&E section shows that the pleomorphic carcinoma formed by the secondary injection of MCF10AβL cells selected for resistance to hypoxia grows within angiogenic stroma with vascular dilation and inflammation. All tissue was formalin-fixed and paraffin embedded. All images are at 20× original magnification.