ACKR1 and cancer: Shi et al. classified ECs from PT and TT into six subgroups based on gene expression: glomeruloid ECs (Endo1: SOST +), cancer-associated ECs (Endo2: NDUFA4L2 +), arterial ECs [Endo3: gap junction protein alpha 5 (GJA5) +], ACKR1 + ECs (Endo4: ACKR1 +), tip cells (Endo5), and CXCR4 + cells (Endo6).