CCL21 and neoplasm: In addition, both stromal cancer-associated fibroblasts within the tumor and mesenchymal fibroblastic reticular cells and lymphatic endothelial cells in the tumor-draining lymph nodes are capable of secreting CCL21 [108, 124], which has been shown to attract CCR7-expressing tolerogenic cell populations (including Tregs and IDO-expressing cells) [88].