CXCL12 and cancer: When we focused on the top-ranked interaction pairs, we found seven source-target gene pairs from CCIDB (i.e. FGL2_FCGR3A, TINAGL1_ITGB1, MDK_LRP1, THY1_ITGB2, CCL5-CD44, SRGN_CD44 and CXCL12_CXCR4) that showed intracellular communication across various cell types, including T cells, myeloid cells, endothelial cells and cancer epithelial cells (Figure 2d).