Meanwhile, basal ROS levels were lower in butein-resistant luminal HER2+ SKBR-3, HCC-1419 and HCC-2218 breast cancer cells than in other cell lines including HER2+ BT-474 and HCC-1569 cells, while basal ROS levels in different breast cancer cells appeared to be independent of breast cancer subtypes. This evidence concerns the gene ERBB2 and breast carcinoma.