TNFSF11 and osteoporosis: This is of particular interest, as the RANKL–RANK axis can be efficiently targeted in the clinic with the blocking anti-RANKL antibody denosumab, which is routinely used for the treatment of osteoporosis or osteolytic bone metastasis (Cummings et al., 2009; Henry et al., 2014) and is currently under investigation for RA treatment (Takeuchi et al., 2019).