Summary of the microarray analysis on WT fetus and Flk1 KO embryos (KO fetus) and ECs. (A) Expression of cell surface marker genes. Most of the putative EC surface markers were present among the 184 genes obtained. The relative intensities of gene expression are shown in the heat map. (B) Expression of transcription factors Ets (Fli1, Etv2, Erg), bHLH (Tal1, Lyl1), Sox (Sox7, Sox 17, and Sox18), Gata2, and Runx1. (C) Expression of tumor endothelial markers. Mirp2 and Cd109 showed high expression in ECs. (D) Expression of genes not previously studied as endothelial-specific genes during early vascular development. These genes were down-regulated in Flk1 KO embryos. (E) Location and motif classification of the 184 genes obtained in the microarray analysis by Ingenuity Pathways Analysis.