Lymphocyte activation gene-3 is associated with programmed death-ligand 1 and programmed cell death protein 1 in small cell lung cancer

BACKGROUND: In recent years, immunotherapy has achieved notable success in cancer treatment. Indeed, the novel immune checkpoint lymphocyte activation gene-3 (LAG3) has shown promising therapeutic efficacy in non-small cell lung cancer. However, it is unclear about the role of LAG3 in immunotherapy and survival in small cell lung cancer (SCLC). METHODS: The expression of LAG3 in SCLC was evaluated in four public datasets. The association of LAG3 with programmed death-ligand 1 (PD-L1), programmed cell death protein 1 (PD-1), and overall survival (OS) was investigated. The LAG3-related biological processes and pathways were identified by functional analyses. RESULTS: LAG3 expression was detected in SCLC tumor tissues. In the cBioPortal dataset with 81 clinical SCLC samples, LAG3 expression was markedly associated with PD-1 and PD-L1 expression (both P<0.050). In addition, Patients with high LAG3 expression had a trend toward a better OS (P=0.073). A similar survival trend was also observed in the GSE60052 dataset. Significantly, LAG3 expression was related to immune-related biological processes, such as immune response, antigen processing and presentation, and T cell co-stimulation (all P<0.001). CONCLUSIONS: This study demonstrated that LAG3 is an important immune checkpoint that is closely associated with PD-1/PD-L1. LAG3 may be a promising novel immunotherapy target for SCLC.