NF1 and neoplasm: Human and murine NF1/Nf1 tumors are replete with macrophages, and macrophage density correlates with tumor growth and malignant transformation.15,25,27,29 Descriptive studies have consistently pointed to an inflammatory signature in these tumors with a preponderance of so-called inflammatory macrophages and high expression of inflammatory cytokines corresponding to a lower-than-expected number of so-called reparative macrophages.