A multi-targeted, small-molecule inhibitor of histone deacetylase (HDAC), epidermal growth factor receptor tyrosine kinase (EGFR/ErbB1), and human epidermal growth factor receptor 2 tyrosine kinase (HER2/neu or ErbB2) with potential antineoplastic activity. HDAC/EGFR/HER2 inhibitor CUDC-101 inhibits the activity of these three enzymes but the exact mechanism of action is presently unknown. This agent may help overcome resistance to inhibition of EGFR and Her2 through a simultaneous, synergistic inhibition of EGFR, Her2, and HDAC.