CSF1 and cancer: Osteolytic cancer cell-derived factors, such as parathyroid hormone like hormone (PTHLH/PTHrP), interleukin (IL)1, IL6, IL8, IL10, receptor activator of nuclear factor kappa B ligand (RANKL), colony stimulating factor 1 (CSF1), tumor necrosis factor α (TNFα) and Jagged1, directly or indirectly stimulate osteoclastogenesis [5, 6].