CLDN5 and central nervous system cancer: The expression of miR-181a is increased in glioma, and miR-181a can inhibit Kruppel-like factor 6 (KLF6) mRNA expression by directly binding to the 3' UTR of KLF6 mRNA; KLF6 can promote the transcriptional expressions of ZO-1, occludin, and claudin-5 mRNAs.