In addition, infiltration of human CD163+ tumor-associated macrophages was evidently detected in a head and neck squamous cell carcinoma engrafted model (45).To specifically increase macrophage development, human macrophage colony stimulating factor (M-CSF; NSG-CSF1) gene was overexpressed in NSG mice (50), which when crossed with NSG-SGM3 mice, led to the generation of NSG-SGM3-CSF1 (QUAD) mice. Here, CSF1 is linked to head and neck squamous cell carcinoma.