Hasegawa [20] found that adult T cell leukemia/lymphoma (ATLL) cells with high CCR7 expression have increased directional migration capability toward CCL21, which suggests that CCR7 expression may facilitate ATLL cell movement to the high endothelial vein of lymph nodes with abundant CCL21, and then to metastasis. Here, CCL21 is linked to adult T-cell leukemia/lymphoma.