CXCL13 and neoplasm: Furthermore, plasma levels of circulating murine RANKL, well-known marker associated with osteoclast activation and bone destruction in MM [32], were significantly increased in tumor-bearing RPMI8226-CXCR4-GFP-inoculated animals compared to control non-injected and RPMI8226-CXCF4-GFP-CRISPR-CXCL13-inoculated mice (Fig. 6H).