STAT3 and cancer: Upon pathogenic invasion, STAT3 signaling regulates the emergency-granulopoiesis and induces a rapid increase in mature neutrophils in the circulation.41 However, this signaling pathway is hyperactivated in the tumor microenvironment of the majority of human cancers, leading to cancer cell survival, therapeutic resistance and immune evasion.24 The prolonged survival and persistence of neutrophils in tumors is another hallmark of protumoral neutrophils.