CXCR4 and ductal breast carcinoma in situ: The estimated signaling direction and received signal highlight the spatial pattern of CXCL from the ligands CXCL9, CXCL10 and CXCL12 to receptors ACKR1 and CXCR4 around three kinds of tumors: DCIS #1, #2 and invasive tumor (Fig. 3G).