As indicated by CCK-8 assay, co-culturing MR macrophages or addition of rhCXCL5 could induce 5-FU-resistance, whereas CXCL5 neutralizing antibody decreased MR macrophages-mediated resistance to 5-FU in gastric cancer cells (Fig. 5G, H). This evidence concerns the gene CXCL5 and gastric cancer.