Nonetheless, previous studies have demonstrated that, compared to luminal breast cancers such as T47D and MCF7 lines, MDA-MB-231 cells have higher ROS [27–29], greater GPX4, SOD1, or SOD2 expression [29, 30], higher protein carbonyls and lipid peroxidation products [29], and lower protein and non-protein thiols [27, 28], the latter of which may be a consequence of high H2O2 levels [31]. This evidence concerns the gene GPX4 and breast cancer.