We previously reported that the HDAC inhibitors TSA and quisinostat suppressed malignancy via changes of the expression of TJ proteins in lung adenocarcinoma, and that TSA also suppressed the proliferation, migration, and invasion of HNSCC cells via p63-mediated tight junction molecules and p21-mediated growth arrest [62,63]. This evidence concerns the gene HDAC9 and head and neck squamous cell carcinoma.