IDH3A and central nervous system neoplasm: More importantly, for the classification of tumors of the central nervous system (WHO CNS5), patients with isocitrate dehydrogenase (IDH) wildtype have a higher expression level of TFRC than those with isocitrate dehydrogenase (IDH) mutations and chromosomal 1p/19q codeletions (Figure 2E, P < 0.00).