Some factors released in the bone microenvironemnt by cancer and stromal cells, including interleukin‐6 (IL‐6) and tumour necrosis factor α (TNF‐α) (Kim et al., 2009), are able to induce osteoclast differentiation in vitro independently of RANK activation (O’Brien et al., 2016). The gene discussed is IL6; the disease is cancer.