Prognostic significance of PD-L1 and CD45RO+cells in glioblastoma: The modulating role of MMR status

Abstract

Background: Glioblastoma (GBM) is the most prevalent and aggressive primary malignant brain tumor with limited treatment options and poor prognosis. Prognostic biomarkers, including immune checkpoint molecules and tumor-infiltrating lymphocytes, offer valuable insights into disease outcomes and potential therapeutic targets. This study uses Immunohistochemical analyses to explore the roles of PD-L1, CD45RO+ cells, and other key biomarkers in GBM prognosis. Methods: Immunohistochemical (IHC) staining of PD-1, PD-L1, CD45RO, mismatch repair (MMR) proteins, and Ki-67 was conducted on 63 formalin-fixed paraffin-embedded (FFPE) GBM tissue samples. Statistical analyses, including Cox regression, assessed the prognostic impact of these biomarkers. Results: IHC staining results indicated limited immune infiltration in the tumor tissue. High PD-L1 expression (HR: 1.926) and elevated CD45RO+ cells infiltration (HR: 2.122) were significantly associated with reduced OS in GBM patients. Subgroup analyses revealed that PD-L1 and CD45RO+ cells had a stronger prognostic impact in MMR-proficient patients, whereas IDH mutation status remained the only independent prognostic marker in MMR-deficient GBM cases. Conclusions: PD-L1 and CD45RO+ cells serve as key prognostic biomarkers in GBM, particularly in MMRproficient patients. These findings underscore the potential for personalized immunotherapies targeting immune checkpoint pathways to improve GBM outcomes. Further research is warranted to explore the therapeutic implications of these markers in GBM subgroups.