Diagnostic Utility of Oncomine Comprehensive Assay v3 in Differentiating Between Isocitrate Dehydrogenase (IDH)-mutated Grade II-III Astrocytoma and Oligodendroglioma.

BACKGROUND/AIM The application of Oncomine Comprehensive Assay v3 (OCAv3) panel in diffuse gliomas (DGs) remains unknown. We investigated the utility of OCAv3-based next-generation sequencing (NGS) in isocitrate dehydrogenase (IDH)-mutated grade II-III DGs. PATIENTS AND METHODS We collected 20 tissue samples obtained from IDH-mutated grade II-III DG patients and performed OCAv3-based NGS. RESULTS By conventional molecular methods, the 20 DGs were classified into seven astrocytomas and 13 oligodendrogliomas. OCAv3 detected all mutations identified in these samples using the conventional methods. The results were highly corroborated by the known mutations in each group. Clustered copy number loss of genes located at the 1p and 19q loci was detected in all 13 oligodendroglioma cases, which harbor the 1p/19q codeletion. CONCLUSION The application of OCAv3-based NGS will improve diagnostic accuracy in DG, with the most beneficial aspects expected in detecting copy number alterations to identify the 1p/19q codeletion correctly.