# Transposable Element Is Predictive of Chemotherapy- and Immunotherapy-Related Overall Survival in Glioma

## TL;DR

This study shows that transposable element expression can predict survival in glioma patients undergoing chemotherapy or immunotherapy.

## Contribution

The study identifies specific transposable elements as novel biomarkers for predicting survival in glioma patients.

## Key findings

- Three transposable elements (LTR81B, LTR27B, MER39B) predict longer survival in glioma patients receiving chemotherapy.
- These elements are linked to immune cell activity and immune checkpoint molecules, influencing treatment outcomes.
- The same transposable elements also predict better survival in patients undergoing immunotherapy.

## Abstract

Background: Glioma is the most common type of malignant brain tumor. Temozolomide (TMZ) is a limited systematic treatment option for glioma, including low-grade glioma (LGG) and glioblastoma (GBM). However, not all patients benefit from TMZ and some develop resistance to it. MGMT methylation has been used to identify patients who may benefit from TMZ, but it is not effective in all cases. Objectives: There is an urgent need for new biomarkers to predict the survival of patients who receive TMZ. Methods: We utilized a recently developed method called REdiscoverTE to precisely measure the expression of transposable elements (TE). We performed Cox regression analysis to assess the predictive ability for prognosis and conducted a series of correlation studies to uncover potential mechanisms. Results: We identified three TEs, LTR81B, LTR27B, and MER39B, that were strongly predictive of longer survival in glioma patients receiving chemotherapy. We discovered that the expression of these TEs was positively associated with immune cells that enhance the immune system and negatively associated with immune cells suppressing the immune response, as well as molecules that control immune checkpoints. These three TEs were also found to predict better survival in patients receiving immunotherapy. Conclusions: In conclusion, we demonstrate that the expression of TEs can serve as a novel biomarker for the overall survival of glioma patients who receive TMZ chemotherapy or immunotherapy.