Through TCGA dataset analysis, we also found that the mRNA expression of several monocyte/macrophage marker genes, including Mrc1 (CD206), CD163, CD68, and ITGAM (CD11b), was significantly upregulated in HNSCC tissues compared to that in adjacent normal tissues, which correlates with advanced clinical stages and poor pathological grades of HNSCC (Supplementary Fig. S3). Here, MRC1 is linked to head and neck squamous cell carcinoma.