Rapid detection of 2-hydroxyglutarate in frozen sections of IDH mutant tumors by MALDI-TOF mass spectrometry

Rémi Longuespée,Aubry K Miller,Peter Schirmacher,Mark Kriegsmann,Stefan Pusch,David E Reuss,Andreas Von Deimling,Christel Herold-Mende,Elena De Vita,Annika K Wefers,Wolfgang Wick

doi:10.1186/s40478-018-0523-3

Abstract

All isocitrate dehydrogenase (IDH) mutant solid neoplasms exhibit highly elevated levels of D-2-hydroxyglutarate (D-2HG). Detection of 2HG in tumor tissues currently is performed by gas or liquid chromatography-mass spectrometry (GC- or LC-MS) or biochemical detection. While these methods are highly accurate, a considerable amount of time for tissue preparation and a relatively high amount of tissue is required for testing. We here present a rapid approach to detect 2HG in brain tumor tissue based on matrix-assisted laser desorption ionization - time of flight mass spectrometry (MALDI-TOF). We analyzed 26 brain tumor samples with known IDH1 or IDH2 mutation and compared readouts to those from 28 brain tumor samples of wildtype IDH status. IDH mutant samples exhibited a clear positive signal for 2HG which was not observed in any of the IDH wildtype tumors. Our analytical pipeline allowed for 2HG detection in less than 5 min. Data were validated by determining 2HG levels in all tissues with a biochemical assay. In conclusion, we developed a protocol for rapid detection of 2HG levels and illustrate the possibility to use MALDI-TOF for the detection of metabolites on frozen tissue sections in a diagnostic setting.

Highlights

Mutations of the isocitrate dehydrogenase genes (IDH1 and IDH2) have been detected in several tumor types including chondrosarcoma, acute myeloid leukemia (AML), cholangiocarcinoma and diffuse glioma [1, 2, 5, 18, 25]
Evaluation of commercially available matrices for detection of a D-2HG solution via matrix assisted laser desorption ionization (MALDI)-time of flight (TOF) We aimed to find a commercially available matrix that allows for the ionization and desorption of 2HG
Evaluation of the matrices Maleic anhydride proton sponge (MAPS) and 1,5-DAN for detection of 2HG in test tissues via MALDI-TOF We evaluated the capacity of 1,5-DAN to detect 2HG in IDH mutant brain tumor tissues, and compared it with the non-commercially available matrix MAPS [12]

Summary

Introduction

Mutations of the isocitrate dehydrogenase genes (IDH1 and IDH2) have been detected in several tumor types including chondrosarcoma, acute myeloid leukemia (AML), cholangiocarcinoma and diffuse glioma [1, 2, 5, 18, 25]. In the diagnosis of brain tumors, the IDH mutation status has gained a dominant role for classification [16]. IDH mutations are present in astrocytoma and oligodendroglioma but absent in other glial/glioneuronal tumors entities constituting differential diagnoses [21]. Mutations predominantly occur in codons 100 and 132 of IDH1 and codons 140 and 172 of IDH2. All these mutations result in a change of substrate specificity.

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