Endothelial Hif-2α deletion leads to reduced tumor growth and increased tumor cell apoptosis. (A) Representative pictures of LLC tumor xenografts from control and KO mice 14 days after subcutaneous injection (n = 9). (B) Weight of tumors excised at day 14. (C) Growth curve of LLC tumors over the 2-week course (n = 9). (D) Representative H&E staining and Ki67 and Apo-BrdU (TUNEL) immunohistochemistry. (E,F) Quantification of Ki67 and TUNEL signals in tumors isolated from control and KO mice (n = 6; * P < .05; **P < .01).