ERBB2 and breast cancer: To further confirm that AST1306 possesses inhibitory activities in ErbB2-overexpressing models, we evaluated the antitumor activity of AST1306 in FVB-2/Nneu transgenic mouse model, which expresses the ErbB2/Neu proto-oncogene and closely recapitulates the ontogeny and progression of human breast cancer [29].