CSF1 and neoplasm: In the endosteal niche, tumor cells are also capable of expressing the Notch ligand Jagged1、vascular cell adhesion molecule (VCAM)1 or by inducing osteogenic cells to produce the osteoclast-stimulating factors macrophage colony stimulating factor (M-CSF) and RANKL to inducing osteoclastic bone formation, which facilitates the renowned ‘vicious cycle’ of osteolytic bone metastasis (94).