Tumor cells can also directly express RANKL and secrete cytokines such as interleukin (IL)-1α, 6, 8, 11; TNF-α; macrophage colony-stimulating factor (M-CSF); or prostaglandin E2 (PGE2), all of which promote osteoclast differentiation and survival, resulting in local osteolysis which supports metastatic growth (110–117). This evidence concerns the gene TNFSF11 and neoplasm.