Lombardi calculated the 2-hydroxyglutarate plasma/urine ratio (normalized by creatinine) in glioma patients, and a statistically significant difference was found between the patients with wild-type and mutant isocitrate dehydrogenase (IDH) 1 when the same cases were histologically confirmed: 15.6 ± 6.8 versus 22.2 ± 8.7 (p < 0.0001). Here, IDH3A is linked to central nervous system cancer.