DNA-methyltransferase inhibitors (DNMTi), such as decitabine and guadecitabine, reverse aberrant methylation and restore expression of antigen-processing genes (TAP1, MHC I/II) while weakening DNA-repair networks, thereby sensitizing GBM to alkylating chemotherapy such as temozolomide (TMZ) (68, 69). The gene discussed is TAP1; the disease is glioblastoma.