GPX4 and breast cancer: Apart from the classical GPX4-GSH axis, there are other antioxidant mechanisms involved in the negative regulation of ferroptosis in breast cancer cells, such as the ferroptosis suppressor protein 1-NADH-CoQ10 (FSP1-NADH-CoQ10) axis (68) and the GCH1 -Tetrahydrobiopterin (GCH1-BH4) axis through the involvement of COQ10 (69), and the regulation of some antioxidant transcription factors, such as NRF2 (70).