Lapatinib effectively inhibits the epidermal growth factor receptors, ErbB1 (EGFR) and ErbB2 (HER2) in breast cancer cells.24, 25 To determine whether these receptors have a role in siramesine and lapatinib-induced cells death, we knocked down HER2 alone, EGFR alone, and then EGFR and HER2 together through transiently using siRNA in MDA MB 231 cells. This evidence concerns the gene EGFR and breast cancer.