CSF1R and rheumatoid arthritis: A range of CSF1R inhibitors are currently under clinical trials [21] for the treatment of cancers including metastatic breast cancer (NCT01596751), ovarian cancer (NCT01525602), colorectal and pancreatic cancer (NCT02777710), solid tumors (NCT02452424) and, for rheumatoid arthritis (NCT01329991).