Furthermore, we found that SPP1+ macrophages were unique to GC cancerous tissues and cancer cell-containing regions, and that the SPP1/CD44-mediated crosstalk between SPP1+ macrophages and cancer cells formed a specific niche to accelerate the malignant progression of GC, which may serve as a therapeutic target with fewer side-effects in GC. The gene discussed is SPP1; the disease is gastric cancer.