Previous studies have shown that serum CEA levels are more elevated in EGFR‐mutated NSCLC patients compared to those with wild‐type EGFR and can predict the efficacy of EGFR‐TKI treatment in NSCLC harboring EGFR mutations [14, 23, 34, 35]. The gene discussed is EGFR; the disease is non-small cell lung carcinoma.