(123B9)2-Motif is a selective agonist of the EphA2 receptor with a dissociation constant (Kd) of 4.9 μM and does not bind to EphA4. It functions by inducing phosphorylation and oligomerization of the EphA2 receptor, promoting receptor activation and internalization. (123B9)2-Motif is primarily used in research on targeted drug delivery for cancers overexpressing EphA2, such as breast cancer, to reduce circulating tumor cells and inhibit metastasis.