TLR4 was overexpressed in human GBM cell lines and tissues, associating with down-expression of Dickkopf 3 (inhibitor of Wnt signaling pathway) and Claudin-5 (protein present in tight junctions), leading to induced Wnt/Claudin signaling to inhibit cell apoptosis and promote GBM progression [66]. Here, CLDN5 is linked to glioblastoma.