CXCR2 and neoplasm: Our data support this hypothesis through two lines of evidence: (1) immunosuppressive factor upregulation: CSN2 (β-casein) inhibits lymphocytes expansion and reduces IFN-γ production by 35–44% in splenocytes [62], and LOC101102413 (haptoglobin) decreases TNF-α secretion in monocytes [63], and (2) immune cell receptor modulation: CSF3R+ myeloid-derived suppressor cells inhibits CD4+CD8+ T cell proliferation [37] and NK cell cytotoxicity [64], and CXCR2+ neutrophils restrain CD8+ T cytotoxicity in tumor to facilitate immune invasion [65].