Gallbladder cancer (GBC), the most common malignancy of the biliary tract, exhibits a high propensity for lymphatic system invasion. However, the mechanisms underlying lymphatic metastasis in GBC remain poorly understood. Here, we demonstrate that C–C motif chemokine ligand 21 (CCL21) is significantly upregulated in GBC and positively correlates with lymphatic vessel density and lymph node metastasis. Both in vivo and in vitro...