CXCR4 and cancer: We produced the drug nanoconjugate T22‐GFP‐H6‐FdU by covalently binding a protein nanoparticle, which selectively targets CXCR4+ cancer cells (Unzueta et al, 2012a; Céspedes et al, 2016) to Floxuridine (FdU), a cytotoxic drug used to treat CRC liver metastases (Shi et al, 2015).