PATH-01. DEVELOPMENT OF A SENSITIVE MULTIPLEX ASSAY FOR DETECTION OF MUTATIONS IN IDH1 AND IDH2

• Published in: Neuro-oncology (Charlottesville, Va.) Va.), 2018-11, Vol.20 (suppl_6), p.vi158-vi158
• Main Authors: Chenn, Anjen, Parker, Scott, Perrey DeGeare, Sarah, Kam-Morgan, Lauren, Cai, Li
• Format: Article
• Language: English
• Subjects: Abstracts
• ISSN: 1522-8517; 1523-5866
• DOI: 10.1093/neuonc/noy148.657

Abstract Isocitrate dehydrogenase 1 and 2 (IDH1 and IDH2) are the most frequently mutated metabolic genes in human cancer. They encode cytosolic and mitochondrial enzymes that catalyze the conversion of isocitrate to a-ketoglutarate (αKG), a key component in metabolic and cellular pathways including the Krebs cycle. All located within exon 4, IDH1 and IDH2 mutations are found in multiple types of human cancer including, but not limited to, acute myeloid leukemia and gliomas. IDH mutations occur in the vast majority of WHO grade II/III gliomas and secondary GBMs. Here we describe a sensitive and robust single base extension assay to detect mutations affecting amino acids 100, 105, and 132 of IDH1, and amino acids 140 and 172 of IDH2 in human clinical specimens. Accuracy studies using FFPE, blood, bone marrow, and synthetic controls showed 100% concordance in mutant identification, confirmed using orthogonal methods. Repeatability (intra-assay precision) and reproducibility (inter-assay precision) were 100%. The assay can detect reliably the presence of 5% mutation in a wild-type background with input as low as 0.25 ng DNA (FFPE). Glioma FFPE stored at 15–30°C were found to be stable for 90 days. The IDH1/IDH2 assay has been offered as a clinical test based on its performance characteristics. In a set of 289 clinical specimens including glioma and AML, results were obtained in >98%. Consistent with other published findings, the majority of mutations in glioma affected R132 of IDH1, with other mutations less frequently identified. This IDH assay has high sensitivity, can reliably detect mutations in FFPE samples, and can be implemented as part of routine clinical practice.