Serum α-1 Acid Glycoprotein is a Biomarker for the Prediction of Targeted Therapy Resistance in Advanced EGFR-positive Lung Adenocarcinoma

Objective: To determine the levels of α-1 acid glycoprotein (ORM1) in the sera of advanced lung adenocarcinoma (LUAD) patients with epidermal growth factor receptor (EGFR) mutation before treatment and after acquirement of EGFR tyrosine kinase inhibitor (EGFR-TKI) resistance, and to explore the clinical cut off value of ORM1 for targeted therapy resistance in LUAD. Methods: Enzyme-linked immunosorbent assay was used to determine serum ORM1 levels. Receiver operating characteristic curve was applied to evaluate the serum ORM1 level in the resistance of EGFR-TKI and the cut off value of ORM1 for the diagnosis of EGFR-TKI resistance. Results: The serum ORM1 concentrations in the healthy group, before and after drug resistance were 1.687 ± 0.103, 1.868 ± 0.101, and 1.731 ± 0.088 μg/ml, respectively. The serum ORM1 concentrations before and after drug resistance were higher than that of the healthy group, whereas the serum ORM1 concentrations in the resistant group were lower than those before drug treatment. In comparison to healthy group, the area under curve (AUC) of the serum ORM1 concentration was 0.918 ± 0.029 with sensitivity of 90.5% and specificity of 78.6% in the patient before EGFR-TKI treatment, while the AUC was 0.644 ± 0.062 with sensitivity of 69.0% and specificity of 66.7% in the resistance group. When compared to those before treatment, the AUC of serum ORM1 concentration was 0.880 ± 0.038 with a sensitivity of 92.9% and specificity of 73.8% in the resistance group. The cutoff value of serum ORM1 was 1.778 μg/ml for advanced EGFR-positive LUAD and 1.723 μg/ml after resistance to EGFR-TKI. Conclusion: Serum ORM1 has an important diagnostic value for the diagnosis of EGFR-positive LUAD and EGFR-TKI resistance in patients especially with advanced EGFR-positive LUAD. Our findings suggest that serum ORM1 is a biomarker in the prediction of EGFR-TKI resistance in EGFR-positive LUAD.