UNC4203(Cat No.:I037836)is a selective, high-affinity small-molecule antagonist of the chemokine receptor CXCR7 (also known as ACKR3), which plays a key role in cell signaling, tumor progression, and immune cell trafficking. By blocking CXCR7, UNC4203 inhibits the binding of its ligands—particularly CXCL12—thereby disrupting downstream signaling pathways involved in cancer cell migration, survival, and angiogenesis. It has been used in preclinical studies to explore the therapeutic potential of targeting the CXCL12/CXCR7 axis in oncology and inflammatory diseases. UNC4203 is a valuable research tool for understanding chemokine receptor biology and tumor microenvironment interactions.