Under the basal iron conditions, the GPX4 level in high-MEMO1 cells was approximately twice higher compared to the knockdown and knockout, both in breast cancer and in melanoma cells, but at the elevated iron level in the growth medium, GPX4 expression in high-MEMO1 cells decreased and no consistent difference was observed between the high- and low-MEMO1 cells (Figure 4—figure supplement 2A–D). Here, GPX4 is linked to melanoma.