The molecular mechanisms of cell death involved in extrinsic, intrinsic, ER stress, caspase-9, caspase-8, and caspase-3 induced atm and atr gene expressions and Bcl-2 family protein expression, whereas the EGFR/MAPK pathway was ameliorated in noninvasive breast cancer MCF-7 but not in invasive MDA-MB-231 cells. This evidence concerns the gene ATR and breast cancer.