TP53 and neoplasm: In addition, while it has been proposed that dysfunctional p53 leads to upregulation of the cystine/glutamate antiporter system xc- in tumor cells and thereby to resistance against ferroptosis induced by oxidative stress (Jiang et al., 2015), pro-apoptotic non-transcriptional mechanisms induce sensitization of tumor cells to ferroptotic death in response to p53 deficiency by re-distribution of the dipeptidyl peptidase 4 to the plasma membrane and subsequent membrane lipid peroxidation (Xie et al., 2017).