CD8A and neoplasm: Activated neutrophils secrete large amounts of IL-1β to promote tumorigenicity of colorectal cells.189 In addition, exosomal miRNA-146a-5p derived from colorectal CSCs promoted stemness and tumorigenicity by targeting Numb of colorectal cells.198 Patients with abundant exosomal miR-146a expression in serum exhibited higher CSCs traits and showed increased tumor-infiltrating CD66+ neutrophils, as well as decreased tumor-infiltrating CD8+ T cells, suggesting the production of an immunosuppressive microenvironment198 (Fig. 4).