HDAC9 and squamous cell carcinoma: Bruzzese et al. demonstrated that the monomodal HDAC inhibitor SAHA in combination with the EGFR tyrosine kinase inhibitor gefitinib induced a synergistic inhibition of proliferation, migration, and invasion, as well as induction of apoptosis in squamous cell carcinoma of head and neck cells, including cells resistant to gefitinib [25].