CCR9 and breast carcinoma: Besides these CCL25-CCR9 and CCL18-PITPNM3 chemokine signaling pathways, other chemokines, such as CCL3 and CCL22, can recruit TAMs, Tregs, and myeloid-derived suppressor cells (MDSCs) during the process of breast cancer metastasis [93]; all of these chemokine signaling pathways are promising targets for inhibiting metastatic breast cancer and are worthwhile to be further examined [196].