TREM2 and neoplasm: TREM2+ macrophages with immunosuppressive properties have also been described in preclinical tumor models43,44, and a similar TREM2 signature has been associated with lipid metabolism and phagocytosis45—a feature that may also correlate with human milk macrophages, which had pathways enriched for ‘lipid metabolic process’ and ‘phagocytosis, engulfment’ (Extended Data Fig. 7e).