In human gastric cancer tissue samples, it has been observed that gastric cancer cells extend the lifespan of neutrophils, with tumor-derived granulocyte–macrophage colony-stimulating factor (GM-CSF) effectively activating neutrophils and inducing PD-L1 expression via the Janus kinase (JAK)-signal transducer and activator of transcription 3 (STAT3) signaling pathway. This evidence concerns the gene STAT3 and gastric cancer.