In vivo administration of the CSF1R inhibitor pexidartinib (PLX3397) depleted M2-polarised macrophages, increased intratumoural CD8+ T-cell density and suppressed both primary tumour growth and pulmonary dissemination in orthotopic and patient-derived xenografts of osteosarcoma (75, 76). The gene discussed is CSF1R; the disease is neoplasm.