Vascular Endothelial Growth Factor Receptor 2 (VEGFR-2), is primarily expressed on vascular endothelial cells. It is the main mediator of VEGF-driven angiogenesis, a process crucial for tumor survival and spread. By inhibiting VEGFR-2, pulocimab blocks downstream pro-angiogenic signals, leading to reduced endothelial cell proliferation and new blood vessel formation within tumors.