TNFSF11 and cancer: RANKL, also known as tumour necrosis factor-related activation-induced cytokine (TRANCE)11, osteoprotegerin ligand (OPGL)12,13 and osteoclastic differentiation factor (ODF)14, interacts with RANK and is involved in all the steps related to tumour development, from initial tumour formation to migration of cancer cells and subsequent metastasis15.