ERBB2 and breast cancer: In order to explore the mechanisms by which Akt1 inhibition promotes breast cancer metastasis, we first used two specific siRNA to knockdown Akt1 in four distinct breast cancer cell lines including MCF-7 (ER+, PR+, HER2−, wild type EGFR, wild type PTEN, wild type p53), BT-474 (ER+, PR+, HER2+, wild type EGFR, wild type PTEN, mutant p53), MDA-MB-231 (ER−, PR−, HER2−, wild type EGFR, wild type PTEN, mutant p53)and SKBR3 (ER−、PR−、HER2+, wild type EGFR, wild type PTEN, mutant p53) cells.