GPX4 and cancer: Intriguingly, certain treatment-resistant cancer cells, such as therapy-resistant mesenchymal cancer cells or drug-tolerant persister cancer cells, are vulnerable to ferroptosis, likely because certain unique state of these cancer cells somehow renders them to be particularly dependent on GPX4 function (Hangauer et al., 2017; Viswanathan et al., 2017); likewise, melanoma cells undergoing dedifferentiation upon BRAF inhibitor treatment also exhibit an increased susceptibility to ferroptosis (Tsoi et al., 2018).