CXCL8 and cancer: The balance of activating and inhibitory receptor expression, cytokine release, and degranulation ability endow NK cells with powerful immune surveillance and direct killing functions toward tumor cells; however, NK cells exhibit a dysfunctional phenotype and exhaustion on tumor development of EC, involving cancer cell-induced over-expression of inhibitory receptors, such as PD-1, and suppression of activated receptors, such as NKp30, tumor infiltrating macrophage-induced CD56dim NK cell apoptosis via H2O2, and aggregation of neutrophils under the influence of IL-8.