Serum Carcinoembryonic Antigen Levels before Initial Treatment are Associated with EGFR Mutations and EML4-ALK Fusion Gene in Lung Adenocarcinoma Patients

Background: Epidermal growth factor receptor (EGFR) mutations and echinoderm microtubuleassociated protein like 4-anaplastic lymphoma kinase (EML4-ALK) define specific molecular subsets of lungadenocarcinomas with distinct clinical features. Our purpose was to analyze clinical features and prognosticvalue of EGFR gene mutations and the EML4-ALK fusion gene in lung adenocarcinoma. Patients and
Methods:EGFR gene mutations and the EML4-ALK fusion gene were detected in 92 lung adenocarcinoma patients inChina. Tumor marker levels before first treatment were measured by electrochemiluminescence immunoassay.
Results: EGFR mutations were found in 40.2% (37/92) of lung adenocarcinoma patients, being identified athigh frequencies in never-smokers (48.3% vs. 26.5% in smokers; P=0.040) and in patients with abnormal serumcarcinoembryonic antigen (CEA) levels before the initial treatment (58.3% vs. 28.6%, P=0.004). Multivariateanalysis revealed that a higher serum CEA level before the initial treatment was independently associatedwith EGFR gene mutations (95%CI: 1.476~11.343, P=0.007). We also identified 8 patients who harbored theEML4-ALK fusion gene (8.7%, 8/92). In concordance with previous reports, younger age was a clinical featurefor these (P=0.008). Seven of the positive cases were never smokers, and no coexistence with EGFR mutationwas discovered. In addition, the frequency of the EML4-ALK fusion gene among patients with a serum CEAconcentration below 5ng/ml seemed to be higher than patients with a concentration over 5ng/ml (P=0.021). Nosignificant difference was observed for time to progression and overall survival between EML4-ALK-positivegroup and EML4-ALK-negative group or between patients with and without an EGFR mutation.
Conclusions:The serum CEA level before the initial treatment may be helpful in screening population for EGFR mutationsor EML4-ALK fusion gene presence in lung adenocarcinoma patients.