In NSCLC patients, Cai et al. [25] pointed out that the EGFR mutation frequencies of patients with CEA level < 5 ug/L, 5–20 ug/L, and > 20ug/L were 39.81%, 45.32%, and 65.47%, respectively (p = 0.004), indicating a positive association between CEA level and EGFR mutation. The gene discussed is CEACAM5; the disease is non-small cell lung carcinoma.