BTNL9 and cavernous hemangioma: The above results suggested that (Figure 4): 1) the ligand-receptor interactions between CXCL12 and CXCR4 play a significant role in the immune responses in cavernous hemangiomas; and 2) the high expression of BTNL9 may cause checkpoint blockade in BTNL9+EC through the binding of BTNL9 to T-cells (Figure 4).