Figure 1.

General C-C Chemokine receptor 7 (CCR7) chemokine dual role in the immune system and breast tumor metastasis. (A) CCR7 role in the adaptive immune system; CCL19/CCL21 chemokine expression activates CCR7 to promote dendritic cells (DC) and T-cell maturation. CCL21 and CCL19 chemokines determine differential signaling. Both chemokines CCL21 and CCL19 have the ability to display G-protein signaling cascades, however only CCL19 can trigger the β-arrestin recruitment. (B) Chemokine receptors in the metastatic process. (As illustrated) CCR7 chemokine receptor activation may play key roles in several steps during the process of metastasis; arrest; dissemination; invasion, extravasation; survival/proliferation) all under the control of the immune system trafficking to the site of inflammation.