We found that ligand-receptor pairs between metastatic tumors and immune cells were significantly upregulated in lymph nodes compared with primary tumors (CCL10-CXCR3, IL34-CSF1R, GAS6-MERTK), indicating that these pathways are critical for the immune response to tumors (Figure 3C). This evidence concerns the gene CXCR3 and metastatic neoplasm.