CXCR4 and cancer: (44–46) Other signaling pathways with established roles in promoting cancer metastasis were also significantly expressed in hybrid cell populations including GAS6-AXL (19) (tumor-hybrid), CXCL12-CXCR4 (20) (hybrid-T cells), LGALS9-P4HB (21) (hybrid-tumor), and IGF1-IGF1R (22–25) (hybrid-tumor).