123B9
123B9, a tumor-homing agent, is a potent and selective EphA2 agonist with a Kd value of 4.0 μM. 123B9 selectively targets the EphA2 tyrosine kinase receptor ligand-binding domain. 123B9 does not appreciably inhibit the ligand binding domains of the most closely related EphA3 and EphA4 receptors.