In addition to DNA-PKcs inhibitors, recent research has indicated that the expression of APLF, a key protein regulating DNA end excision in NHEJ, increased in radiation-resistant glioblastoma cells, suggesting that it may be a useful novel target for glioblastoma radiotherapy.521 Another study found that thymine DNA glycosylase (TDG) can regulate the NHEJ pathway through demethylation of cytosine-guanine (CpG) islands in the TAZ gene, thereby enhancing esophageal cancer cell proliferation and radiation resistance.522. The gene discussed is PRKDC; the disease is glioblastoma.