HDAC inhibitors trichostatin A (TSA) and an inhibitor of HDAC1 and HDAC6, prevent cell proliferation, migration and invasion of human head and neck squamous cell carcinoma (HNSCC) by downregulation of p63-mediated tight junction molecules JAM-A and CLDN-1, and induction of p63 or p21-mediated growth arrest [100]. Here, HDAC9 is linked to head and neck squamous cell carcinoma.