Understanding the Genomic Landscape of Glioblastoma: Opportunities for Targeted Therapies

Abstract

Glioblastoma (GBM) is categorized by the World Health Organization (WHO) as a grade 4 glioma and is a uniformly fatal tumor of the central nervous system. With the discovery of specific gene anomalies, GBM classification has been modified several times to provide better diagnostic and prognostic accuracy. Survival outcomes remain dismal despite the current therapeutic modalities, which include a combination of surgical resection, adjuvant chemotherapy, and radiotherapies, providing brief control of tumor progression. GBM remains aggressive and reoccurs primarily due to the presence of a unique population of untreatable glioblastoma stem cells (GSC). The presence of high mutation rates and a dysregulated transcriptional landscape increase GSC resistance to conventional chemotherapy and radiation therapy, contributing to poor outcomes seen in GBM patients. Accordingly, GSCs have emerged as targets of interest in new GBM treatment paradigms. Consequently, it is important to understand their distinct properties, such as GSC interactions with the hypoxic microenvironment, enhancing their growth. The epigenomic regulators and fundamental molecular components of the signaling pathways represent potential targets for GBM therapies. In this review, we aimed to describe the evolution of GBM classification and highlight the current therapeutic modalities, including gene and immunotherapies, and mammalian target of rapamycin (mTOR) inhibitors to target GBM. Furthermore, we explored the molecular pathway of GSCs and the ongoing investigation of circulating tumor cells (CTC), along with precision therapeutics, which aim to provide novel discoveries and effective treatments for GBM with improved survival.

Keywords: Glioblastoma; immunotherapy; mTOR-related targeted therapy; review; stem cell.