AHR and cancer: In this study, the higher fold change (FC) in EGFR-mutant NCI-H1975 cells suggests that PM2.5 may enhance resistance to EGFR-targeted therapies, aligning with research showing that PM2.5 promotes lung carcinogenesis by inducing inflammation, oxidative stress, and DNA damage, selecting for EGFR mutations that drive oncogene activation, tumour progression, metastasis, and drug resistance, while AhR-Src signalling fosters cancer proliferation and EGFR-TKI resistance [8,9,10].