Definition

A small molecule and orally available inhibitor of colony-stimulating factor-1 receptor (CSF1R; FMS) with potential antineoplastic activity. FMS tyrosine kinase inhibitor JNJ-40346527 blocks the receptor-ligand interaction between FMS and its ligand CSF1, thereby preventing autophosphorylation of FMS. As a result, unphosphorylated FMS cannot activate FMS-mediated signaling pathways, thus potentially inhibiting cell proliferation in FMS-overexpressed tumor cells. FMS, a tyrosine kinase receptor, is overexpressed in certain tumor cell types and plays an essential role in macrophage differentiation, recruitment, and activation as well as the regulation of cell proliferation.