In the past decades, many chemoresistance mechanisms have been reported, such as the expression of the DNA repair protein MGMT, drug efflux transporters, gap junction activity, DNA mismatch repair, DNA base excision repair, poly (ADP)-ribose polymerase repair system, the presence of glioma stem cells, upregulation of cell survival autophagy, the DNA double strand break repair, and the up-regulation of components of the ubiquitin proteasome system with oncogenic activity 25-31. The gene discussed is MGMT; the disease is central nervous system cancer.