CCR7 and breast carcinoma: However, while the complete picture on the role and involvement of CCL21/CCR7 pair in breast cancer is still undergoing development, there are at least two areas in which this axis has shown to be actively involved, often through vascular endothelial growth factor C (VEGF-C) mediated signaling, namely: lymph nodes metastasis, and immune response modulation [18-23].