Association of Divergent Carcinoembryonic Antigen Patterns and Lung Cancer Progression

Changes in expression patterns of serum carcinoembryonic antigen at initial diagnosis (CEA^In) and disease progression (CEA^Pd) in lung cancer patients under EGFR-tyrosine kinase inhibitors (TKI) treatment may reflect different tumor progression profiles. Of the 1736 lung cancer patients identified from the cancer registry group between 2011 to 2016, we selected 517 patients with advanced stage adenocarcinoma, data on EGFR mutation status and CEA^In, among whom were 288 patients with data on CEA^Pd, eligible for inclusion in the correlation analysis of clinical characteristics and survival. Multivariable analysis revealed that CEA^In expression was associated with poor progression-free survival in patients harboring mutant EGFR. Moreover, CEA^In and CEA^Pd were associated with the good and poor post-progression survival, respectively, in the EGFR-mutant group. Cell line experiments revealed that CEA expression and cancer dissemination can be affected by EGFR-TKI selection. EGFR-mutant patients, exhibiting high CEA^In (≥5 ng/mL) and low CEA^Pd (<5 ng/mL), showed a potential toward displaying new metastasis. Taken together, these findings support the conclusion that EGFR mutation status is a critical factor in determining prognostic potential of CEA^In and CEA^Pd in patients under EGFR-TKI treatment, and CEA^In and CEA^Pd are associated with distinct cancer progression profiles.