Identification of in vivo–expressed EC-specific and BEC and LEC sublineage-specific genes. (A) Pan-EC–specific gene expression. Genes that are differentially expressed in ECs (pooled data of BECs and LECs) and non-ECs (pooled data of FBs, MCs, CD14⁺ DDCs, CD1a⁺ DDCs, LCs, and KCs) were identified by variance analysis as described in “Materials and methods.” In the Volcano presentation of data, the mean logarithmic expression difference (x-axis) and the statistical confidence of differential expression (P value, y-axis) are shown for each individual identified gene. The identification of several established pan-EC gene products (VEGFR2/KDR, angiopoietin receptor 2/TIE2, von Willebrand factor/VWF, VE-caherin/CD144) in the group of gene products whose expression is highly overrepresented in ECs validates the quality of cell samples and the statistical approach. (B-C) Identification of in vivo expressed, LEC- and BEC-specific genes. Genes that are differentially expressed in LECs and non-LECs (pooled data of BECs and the other skin cell types) (B), or in BECs and in non-BECs (pooled data of LECs and the other skin cell types) (C), were extracted and the mean logarithmic expression difference (x-axis) and P values of differential expression (y-axis) for each identified gene are shown. Arbitrary cut offs for statistically significant EC-specific and EC subtype-specific gene expression (> 10-fold expression difference, P < 10⁻⁴) are marked by dotted lines in all volcano plots.