In addition, the concentrations of CCL18 in culture supernatants from MS and MR macrophages were very low and the difference was not statistically significant (Fig. 5C, D; HGC27: p = 0.149; MKN45: p = 0.372), which could not explain the difference between MS and MR macrophages in enhancing 5-FU-resistnace of gastric cancer cells. Here, CCL18 is linked to gastric cancer.