Because several studies have confirmed that both BMSCs and osteoblasts express tyrosine receptor kinase B (TrkB), the high-affinity receptor of BDNF on their surface [23], [24], these findings suggest that osteoclastogenesis in myeloma may be promoted by BDNF partially through myeloma-stroma interactions that induce RANKL secretion in the BM microenvironment. The gene discussed is NTRK2; the disease is plasma cell myeloma.