PECAM1 (CD31) and CDH5 (VE-cadherin) are pan-endothelial markers confirming endothelial identity, while MECOM and ENPEP further support this. PCSK5, GJA5 (connexin 40), and NEBL show enriched expression in arterial endothelial cells, with GJA5 mediating gap junction communication characteristic of arterial vessels. Together these markers identify arterial ECs and distinguish them from capillary, venous, and lymphatic endothelial subtypes.