TNFSF11 and rheumatoid arthritis: We recently demonstrated that geranylgeranylacetone (GGA), a nontoxic inducer of heat shock protein, used as an antiulcer drug, potently inhibits human osteoclastogenesis induced by soluble RANKL [6] and also induces cell death in fibroblast-like synoviocytes (FLS) from patients with RA by inhibiting protein geranylgeranylation [7].