CXCR4 and neoplasm: However, pertaining to the co-stimulatory effects of chemokine receptors in TCR-mediated T cell activation (35, 47, 59), we also argue that outfitting BCMA CAR-expressing NK-92 cells with CXCR4 endows these cells with an enhanced ability to kill BCMA antigen-expressing tumor cells on a cellular level.