In RA, experimental and translational studies suggest that enhanced activity of the classical axis within synovial tissue is associated with synovial inflammation, fibroblast-like synoviocyte survival, angiogenesis, and bone erosion through pathways involving nuclear factor kappa B (NF-kB), mitogen-activated protein kinase (MAPK), and receptor activator of nuclear factor kB ligand (RANKL)/Wingless-related integration site (Wnt) signaling pathway. The gene discussed is TNFSF11; the disease is rheumatoid arthritis.