Introduction: Previous magnetic resonance spectroscopy (MRS) and mass spectroscopy studies have shown accumulation of 2-hydroxyglutarate (2HG) in mutant isocitrate dehydrogenase (IDH) gliomas. IDH mutation is known to be a powerful positive prognostic marker in malignant gliomas. Hence, 2HG accumulation in gliomas was assumed to be a positive prognostic factor in gliomas, but this has not yet been proven. Here, we analyzed 52 patients harboring World Health Organization (WHO) grade II and III gliomas utilizing 3.0-tesla MRS.
Results: Mutant IDH gliomas showed significantly higher accumulation of 2HG (median 5.077 vs. 0.000, p = 0.0002, Mann-Whitney test). 2HG was detectable in all mutant IDH gliomas, whereas in 10 out of 27 (37.0%) wild-type IDH gliomas, 2HG was below the detectable range (2HG = 0) (p = 0.0003, chi-squared test). Screening for IDH mutation by 2HG analysis was highly sensitive (cutoff 2HG = 1.489 mM, sensitivity 100.0%, specificity 72.2%). Gliomas with high 2HG accumulation had better overall survival than gliomas with low 2HG accumulation (p = 0.0401, Kaplan-Meier analysis).
Discussion: 2HG accumulation detected by 3.0-tesla MRS not only correlates well with IDH status, but also positively correlates with survival in WHO grade II and III gliomas.