We compared the expression differences between metastatic cancer and primary cancer and found that, apart from a significant downregulation of CXCL14 and CCL28, as well as a significant upregulation of CXCL12 and CCL2, the expression levels of most chemokines did not achieve a twofold change (Figure 1A,B, Supplementary Table S2, Supplementary Data S2). Here, CCL2 is linked to cancer.