TNFSF11 and cancer: Although CXCR2 has a high affinity for Interleukin-8 (IL-8) and GROα and a low affinity for GROβ, GROβ/CXCR2 loops may play an important role in the development and maintenance of certain type of human cancer, involving activation of NF-κB and other possible signaling pathways, including RANKL, AKT, STAT3, and MAPK [39, 40].