Clinical Significance of Soluble LAG-3 (sLAG-3) in Patients With Cervical Cancer Determined via Enzyme-Linked Immunosorbent Assay With Monoclonal Antibodies
Yang Li, Wenwen Wang, Jingluan Tian, Ying Zhou, Yu Shen, Mingyuan Wang, Longhai Tang, Cuiping Liu, Xueguang Zhang, Fangrong Shen, Youguo Chen, Yanzheng Gu
Abstract
Background: The tumor microenvironment and tumor immunity have become the focus of research on tumor diagnosis and treatment. Lymphocyte activation gene-3 (LAG-3, CD223) is a newly discovered immunosuppressive receptor that is abnormally expressed in various tumor microenvironments and plays an important role as an immune checkpoint in the tumor immune response. Objective: We developed a novel enzyme-linked immunosorbent assay kit, examined the levels of soluble LAG-3 (sLAG-3) in the serum of patients with cervical cancer, and identified new biomarkers for cervical cancer development. Methods: To investigate the potential biological function of sLAG-3, we generated and characterized 2 novel anti-LAG-3 monoclonal antibodies, namely 4F4 and 4E12. We performed western blotting, immunofluorescence, and immunohistochemistry using hybridoma technology and an enzyme-linked immunosorbent assay kit for detecting human sLAG-3 based on an improved double-antibody sandwich enzyme-linked immunosorbent assay method. The stability and sensitivity of these kits were also assessed. Results: We screened and characterized 2 novel monoclonal antibodies against human LAG-3. The enzyme-linked immunosorbent assay kit also includes a wide range of tests. Using this enzyme-linked immunosorbent assay system, we found that the expression level of sLAG-3 in the peripheral blood of patients with cervical cancer significantly decreased as the disease progressed ( P < .0001). Multivariate logistic regression analysis revealed that low sLAG-3 expression was an independent predictor of cervical cancer and related diseases ( P < .05). Furthermore, receiver operating characteristic curve analysis showed that sLAG-3 had diagnostic value for cervical cancer metastasis ( P < .0001). Conclusion: These data suggest that sLAG-3 is a potential biomarker for cervical cancer development. Therefore, this kit has a certain application value in the diagnosis of cervical cancer.