CSF1 and cancer: Colony-stimulating factor 1 receptor (Csf1r) is a transmembrane tyrosine kinase receptor and the primary homeostatic regulator of the mononuclear phagocytic system, which includes KCs.[11] Csf1r and its ligand, monocyte colony-stimulating factor 1 (M-CSF; CSF1), regulate macrophage proliferation, function, survival, and migration.[11, 12] Therapies involving Csf1r and M-CSF are currently under investigation in clinical trials for cancer, inflammatory diseases, and tissue repair.[11] The effects of inhibiting or stimulating Csf1r in normal animals during LR are unknown.