EGFR and non-small cell lung carcinoma: NSCLC patients with low-abundance EGFR mutation may experience reduced ORR and shorter PFS time compared to groups with high-abundance EGFR mutation.[15,16] Data from these studies indicate that treatment with EGFR-TKI for the patient in our case would probably be relatively ineffective, and the patient did indeed experience primary resistance to EGFR-TKI therapy.