The receptor tyrosine kinase-like orphan 1 (ROR1) is a transmembrane protein expressed during embryonic development. Moreover, it is highly expressed on the surface of several cancer cell types, including B-cell malignancies and solid tumors such as triple-negative breast cancer (TNBC). Researchers from The University of Queensland and collaborating institutions recently reported the development of a single-chain fragment variable (scFvs) specifically targeting the membrane proximal region of ROR1 rather than the Ig-like domain, aiming to reduce cross-reactivity with other surface proteins expressed in normal tissues.