TMIC-64. Multiomic analyses for tumor microenvironment with tertiary lymphoid structures in glioblastoma

Abstract BACKGROUND Recently, the presence of tertiary lymphoid structure (TLS), composed mainly of intratumoral B cells, has been reported as a favorable prognostic factor in various types of cancer. However, TLS has not been well studied in glioblastoma. In this study, we performed spatial and genomic analyses in human glioblastoma, focusing on TLS. METHODS We evaluated lymphocytic infiltration by immunostaining in 50 cases, which were diagnosed with glioblastoma from April 2018 to March 2023 in Okayama University Hospital. RNA-sequencing (RNA-seq) was performed in 39 cases to compare those with and without TLS by Differential Gene Expression (DGE) analysis and Gene Set Enrichment Analysis (GSEA). In addition, we performed spatial transcriptomic analysis using the tissue sections with TLS. RESULTS TLS was detected in 4 (8.0%) of the 50 cases. DGE analysis showed increased gene expression related to the T cell activation marker (TNFRSF9), chemokine (CCL5), etc., in patients with TLS. GSEA also confirmed the activation of immune responses such as Adaptive immune response, Cytokine production, and Lymphocyte activation etc. Spatial transcriptomic analysis revealed the local upregulation of genes detected by RNA-seq analysis in and around TLS region. Moreover, it seemed to be the secondary lymphoid follicles and follicular helper T cells in TLS, which suspected the presence of mature TLS. CONCLUSION We analyzed a total of 50 cases of glioblastoma. Glioblastoma with TLS were immune activated.