As for the combination of CXCR4 and CXCL12 levels, CXCR4high/CXCL12high in GC is significantly associated with tumor invasion depth, LN involvement, and higher TNM stage, which causes the worst prognosis, whereas patients with CXCR4low/CXCL12low show the best prognosis 22. The gene discussed is CXCL12; the disease is gastric cancer.