Research progress of drug resistance mechanisms to temozolomide in glioblastoma: A narrative review

Glioblastoma multiforme (GBM) is the most common malignant tumor in the adult central nervous system, and surgery combined with radiotherapy and chemotherapy represents the main treatment regimens. Temozolomide (TMZ) is currently the first-line chemotherapeutic agent used in GBM therapy and is widely used subsequent with surgical resection of GBM. TMZ can significantly prolong the survival time of patients with glioma. However, the high incidence of resistance to TMZ, which seriously affects the overall outcome of GBM treatment, is a serious concern facing clinicians. The mechanisms of resistance to TMZ in patients with GBM include biological processes involving DNA damage repair, cellular autophagy, glioma stem cells, and the tumor microenvironment. Therefore, exploring the mechanisms inducing GBM resistance to TMZ treatment and how to effectively reduce TMZ resistance and improve its efficacy has become an urgent question. This review summarizes the effects and mechanisms of TMZ resistance in the treatment of glioma. It is hoped that intensive investigation of the mechanisms of resistance of TMZ to GBM can lay the foundation for successful outcomes in patients with GBM.