IDH1 and glioma: For example, RAD51 recombinase, an enzyme that plays major roles in the HR process, protects IDH-mutated cells from temozolomide-induced DNA damage.82 Nunez et al.83 showed that the depletion of TP53 or ATRX on an IDH-mutated background resulted in glioma cells tending to undergo a DNA damage response, highlighted by upregulated ATM signalling and resistance to radiotherapy.