Analysis of CEA Expression and EGFR Mutation Status in Non-small Cell Lung Cancers

Background: The serum carcinoembryonic antigen (CEA) level can reflect tumor growth, recurrence andmetastasis. It has been reported that epidermal growth factor receptor (EGFR) mutations in exons 19 and 21mayhave an important relationship with tumor cell sensitivity to EGFR -TKI therapy. In this study, we investigatedthe clinical value of EGFR mutations and serum CEA in patients with non-small cell lung cancer (NSCLC).Materials and
Methods: The presence of mutations in EGFR exons 19 and 21 in the tissue samples of 315 patientswith NSCLC was detected with real-time fluorescent PCR technology, while the serum CEA level in cases who hadnot yet undergone surgery, radiotherapy, chemotherapy and targeted therapy were assessed by electrochemicalluminescence.
Results: The mutation rates in EGFR exons 19 and 21 were 23.2% and 14.9%, respectively, withthe two combined in 3.81%. Measured prior to the start of surgery, radiotherapy, chemotherapy and targetedtreatment, serum CEA levels were abnormally high in 54.3% of the patients. In those with a serum CEA level <5ng/mL, the EGFR mutation rate was 18.8%, while with 5~19 ng/mL and ≥20 ng/mL, the rates were 36.4% and62.5%. In addition, in the cohort of patients with the CEA level being 20~49 ng/mL, the EGFR mutation rate was85.7%, while in those with the CEA level ≥50 ng/mL, the EGFR mutation rate was only 20.0%, approximatelythe same as in cases with the CEA level<5 ng/mL.
Conclusions: There is a positive correlation between serumCEA expression level and EGFR mutation status in NSCLC patients, namely the EGFR mutation-positive rateincreases as the serum CEA expression level rises within a certain range (≥20 ng/mL, especially 20~49 ng/mL).If patient samples are not suitable for EGFR mutation testing, or cannot be obtained at all, testing serum CEAlevels might be a simple and easy screening method. Hence, for the NSCLC patients with high serum CEA level(≥20 ng/mL, especially 20~49 ng/mL), it is worthy of attempting EGFR-TKI treatment, which may achieve betterclinical efficacy and quality of life.