cFMS Receptor Tyrosine Kinase Inhibitor is a selective cell-permeable diaminopyrimidine compound that inhibits colony-stimulating factor (CSF)-1 resulting in suppression of monocyte growth and bone degradation in vitro and inhibits CSF-1 signaling through cFMS kinase. In addition, studies show that cFMS Receptor Tyrosine Kinase Inhibitor inhibits nuclear factor B ligand, a molecule responsible for osteoclast differentiation. Further studies confirmed that the inhibitor partially inhibits thioglycolate-induced cell influx into the peritoneal cavity and completely suppresses the growth of CSF-1-dependent tumor cells and M-NFS-60 myeloid cells.