CCL21 and neoplasm: While some recent data pointed to the importance of the CCL21-CCR7 axis during tumor-lymphatic chemo-attraction [8,9], we also noted that CCL21 is endowed with a C-terminus that is particularly rich in basic amino acids that may contribute to heparin binding [44], which we confirmed by heparin affinity chromatography using recombinant CCL21 (Figure 5A).