J Pathol Transl Med.  2019 Sep;53(5):298-307. 10.4132/jptm.2019.07.15.

Reclassification of Mongolian Diffuse Gliomas According to the Revised 2016 World Health Organization Central Nervous System Tumor Classification

• Ochirjav E
• Enkhbat B
• Baldandorj T
• Choe G

• KMID: 2459578
• DOI: http://doi.org/10.4132/jptm.2019.07.15

Abstract

BACKGROUND
The 2016 World Health Organization (WHO) classification of central nervous system (CNS) tumors has been modified to incorporate the IDH mutation and 1p/19q co-deletion in the diagnosis of diffuse gliomas. In this study, we aimed to evaluate the feasibility and prognostic significance of the revised 2016 WHO classification of CNS tumors in Mongolian patients with diffuse gliomas.
METHODS
A total of 124 cases of diffuse gliomas were collected, and tissue microarray blocks were made. IDH1 mutation was tested using immunohistochemistry, and 1p/19q co-deletion status was examined using fluorescence in situ hybridization analysis.
RESULTS
According to the 2016 WHO classification, 124 cases of diffuse brain glioma were reclassified as follows: 10 oligodendroglioma, IDH

Keyword

World Health Organization; Classification; Glioma; Isocitrate dehydrogenase; Chromosome deletion

MeSH Terms

Astrocytoma
Brain
Central Nervous System
Chromosome Deletion
Classification
Diagnosis
Fluorescence
Glioblastoma
Glioma*
Global Health*
Humans
Immunohistochemistry
In Situ Hybridization
Isocitrate Dehydrogenase
Nervous System Neoplasms*
Nervous System*
Oligodendroglioma
World Health Organization*
Isocitrate Dehydrogenase

Figure

• 

  Fig. 1. IDH1 immunohistochemical staining of diffuse brain glioma. (A) Definite fried egg appearance (perinuclear halo) of oligodendroglioma in hematoxylin and eosin (H&E) staining ×100. (B) The tumor cells express IDH1 in the cytoplasm by immunohistochemistry. The unstained cells in the brain parenchyma represent non-neoplastic cells. (C) H&E staining of anaplastic astrocytoma with pleomorphic nucleus ×100. (D) The tumor cells are negative for IDH1 immunostaining.

• 

  Fig. 2. Fluorescence in situ hybridization (FISH) analysis of 1p/19q co-deletion on formalin-fixed paraffin-embedded specimen: (A) FISH preparation showing 1p deletion in an oligodendroglioma. A tumor cell in 1p deletion status is clearly seen, with a 2:1 ratio of control (green) signals and target (red) signal. (B) FISH preparation showing 19q deletion in the same oligodendroglioma case. One cell is labeled showing one red signal for the 19q test probe and two green signals for the 19q control probe, indicating loss of one copy of 19q.

• 

  Fig. 3. Change in diagnosis after applying molecular genetics integrated diagnostic criteria according to the updated 2016 WHO classification. WHO, World Health Organization; IDHmut, isocitrate dehydrogenase mutant; IDHwt, NOS, isocitrate dehydrogenase wildtype, not otherwise specified; 1p/19q codel, 1p/19q co-deleted.

• 

  Fig. 4. Kaplan-Meier curves for overall survival according to the 2007 WHO classification (A, C, E) and 2016 WHO classification (B, D, F), respectively. (A, B) For all tumors. (C, D) For grade II tumors. (E, F) For grades III and IV tumors. WHO, World Health Organization.

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