CSF1R and neoplasm: Sunitinib inhibits RTKs expressed by tumor cells that are involved in tumor cell proliferation and survival including stem cell factor receptor (c-KIT), Fms-related tyrosine kinase 3 (FLT3), the glial cell-line derived neurotrophic factor receptor (RET) and colony-stimulating factor type 1 receptor (CSF-1R) [18], [19].