Contribution of the different VE-cadherin–expressing cells to the tumor vasculature of unperturbed tumors. (A) Immunohistochemical analysis of β-gal expression in bone marrow sections and sections of subcutaneous growing c-neu transformed mammary epithelial tumors in 5 different mouse models is shown: (Aa-b) constitutive VE-cadherin-Cre/R26R mice (VECAD), (Ac-d) bone marrow transplantation of constitutive VECAD mice in lethally irradiated wild-type (WT) C57BL/6, (Ae-f) inducible CIVE mice, (Ag-h) bone marrow transplantation of CIVE mice in lethally irradiated WT C57BL/6 mice, and (Ai-j) bone marrow transplantation of WT C57BL/6 mice into lethally irradiated CIVE mice. (B) The fluorescent versions of the above models with EYFP instead of lacZ expression were used for FACS analysis of subcutaneous growing c-neu transformed mammary epithelial tumors. The graph depicts the percentage of EYFP⁺ cells in the tumors. (C-F) Shown is the immunohistochemical analysis of β-gal (and CD31 expression for [E] and [F]) in the tumors of the constitutive VE-cadherin transplantation into (C-E) WT C57BL/6 mice and (F) the WT C57BL/6 transplantation into CIVE mice. All images were 20× except for (D) (63×) and (F) (40×).