In our result, though CCR7 is inhibited by miR-21 in early stage LSCC and CCL21 expression is decreased in middle stage LSCC, cancer cells through the upregulation of CCR7 in middle stage LSCC to increase the binding probability to interact with chemoattractant CCL21 can promote themselves to migrate to lymph nodes (Figure 3). Here, CCL21 is linked to cancer.