CSF1 and neoplasm: Furthermore, while F4/80hiMHCIIlow macrophages do not require CCR2+ monocytes for their maintenance in the healthy gut LP or in tumours, we found that F4/80hiMHCIIhi macrophages become independent from CCR2+ monocytes in tumours only, potentially due to tumour-derived colony stimulating factor-1 (CSF1) that supports macrophage self-renewal.