It usually forms a highly conserved unhooking endonuclease complex with XPF that stabilizes both proteins for their roles in ICL repair and HR.21 In addition to ERCC1, our study also observed that XPF mRNA expression was decreased in EGFR exon 19 deletion NSCLC cells as compared with EGFR wild‐type ones (Fig S1c). This evidence concerns the gene ERCC4 and non-small cell lung carcinoma.