S100A8 and neoplasm: Notably, one of the most downregulated genes in the tumor in VSIRKO mice was S100A8, which is an established marker of immunosuppressive macrophages.25 Gene set enrichment analyses revealed that both phagocytosis and antigen presentation pathways were significantly enriched in macrophages from the VSIRKO compared with those from VSIRWT mice (Figure 4C).