In the present study, we used double-knockout mice for CCR1 and CXCR2 in BM transfer experiments (Figs. 5 and 6), and discovered that simultaneous deletion of both CCR1 and CXCR2 entirely inhibited neutrophil mobilization, thereby significantly suppressing tumor growth and metastasis. The gene discussed is CXCR2; the disease is neoplasm.