We therefore performed single cell RNA sequencing (scRNAseq) on EGFR mutant PC9 non-small cell lung cancer persister cells, derived from 10 days of treatment with EGFR inhibitor erlotinib, which were subsequently treated with GPX4 inhibitor RSL3 for 24 hours resulting in partial death and effectively purifying surviving persister cells. The gene discussed is GPX4; the disease is non-small cell lung carcinoma.