Given the critical importance of ErbB receptors in maintaining the neoplastic properties of a variety of cancers and the incompletely met medical need for effective cancer treatment, the results of the present study, combined with the better pharmacokinetic profiles and well-tolerated toxic settings (unpublished data), indicate that AST1306 deserves further study, especially in the context of human tumors that overexpress ErbB2 and/or harbor secondary mutations in their ErbB receptors. This evidence concerns the gene ERBB2 and cancer.