Xenografted tumours were excised for HE staining at 7th week, and the results manifested that the presence of PNI in CXCL12 group, saline group, AMD3100 group was 85.7% (6/7), 16.7% (1/6) and 0 (0/7), respectively. The gene discussed is CXCL12; the disease is neoplasm.