IDH3A and neoplasm: Likewise, this finding might be caused by substantial heterogeneity in patient-specific tumor cell lines, causing different radiation sensitivity as, for example, T76 and H19 showed both isocitrate dehydrogenase (IDH) wildtype and O6-methylguanine-DNA methyltransferase (MGMT) was not methylated, whereas H9 was IDH mutated and MGMT was methylated.