METHODS: We employed an integrated multi-omics approach in erlotinib-sensitive and resistant NSCLC cells, including genome-wide mapping of abasic sites (AP sites) via Single-Strand Break Mapping at Nucleotide Genome Level-AP (SSiNGLe-AP), characterization of binding landscapes of 8-Oxoguanine DNA Glycosylase 1 (OGG1), Apurinic/Apyrimidinic Endonuclease 1 (APE1), and genome-wide profiling of G-quadruplex (G4) structures by Cleavage Under Targets and Tagmentation sequencing (CUT&Tag-seq). Here, APEX1 is linked to non-small cell lung carcinoma.