Galectin-9: A Predictive Biomarker Negatively Regulating Immune Response in Glioma Patients

Glioma is the most frequent primary brain tumor. Immunotherapy is one of the most promising therapeutic approaches for gliomas. T cell immunoglobulin domain and mucin domain-3 can induce the malignancy of gliomas. The function of galectin-9 (GAL-9), as one of the ligands of T cell immunoglobulin domain and mucin domain-3, in glioma has remained elusive. The aim of this study was to characterize the expression of GAL-9 in patients with glioma. This study enrolled 1292 patients with glioma from the GSE 16011 array set, the Chinese Glioma Genome Atlas, and The Cancer Genome Atlas datasets. Kaplan-Meier analysis was undertaken to explore the prognostic value of GAL-9. Graphpad software and R language were used for statistical analysis. Expression of GAL-9 was highly correlated with major clinical and molecular features. Patients with high expression of GAL-9 were more susceptible to development of malignant tumors. Gene Ontology analysis revealed that expression of GAL-9 was closely associated with function of immune response in glioma. Clinically, the results of Kaplan-Meier analysis showed that expression of GAL-9 was negatively associated with overall survival in all grades of glioma including high-grade gliomas. High expression of GAL-9 was an independent indicator of poor prognosis. Our results highlight the pivotal role of GAL-9 in regulation of immune suppressive features of gliomas and indicate that GAL-9 is a promising target for cancer immunotherapy and may lead to development of further therapies.