We confirmed that CCL18 was mainly secreted by M2 macrophages (Fig. 2e) and HCC patients displayed a higher proportion of CD68+CD206+CCL18+ macrophages in tumor significantly associated with large tumor size (P = 0.025), advanced TNM stage (P = 0.034; Supplementary Table S4), and poor survival (Fig. 2f, P = 0.001; Supplementary Fig. S2f) in our cohort. This evidence concerns the gene MRC1 and hepatocellular carcinoma.