IDH1, IDH2, and TERT Mutation Analysis, Next-Generation Sequencing, Tumor

Casandra

Casandra Test Code MC35298Version 1 (DRAFT)

Performing Lab

Lab Mayo Clinic LabLab Test ID IDTRTCPT Codes 0481, 88381

IDH1, IDH2, and TERT Mutation Analysis, Next-Generation Sequencing, Tumor

Clinical Use

Use

The IDH1 and IDH2 genes encode enzymes involved in cellular glucose metabolism. Mutations in these genes, specifically at codons R132 in IDH1 and R140 and R172 in IDH2, contribute to tumorigenesis by generating the oncometabolite R(-)-2-hydroxyglutarate. The TERT promoter mutations, commonly occurring in hotspot positions c.-124 (C228) and c.-146 (C250), lead to increased telomerase activity, allowing tumor cells to surpass cellular senescence. This test evaluates these somatic mutations within solid tumor samples to assist in tumor diagnosis and classification.

Special Instructions

This test evaluates somatic mutations within solid tumor samples and does not assess germline alterations. A pathology review and macrodissection to enrich for tumor cells is performed prior to testing. A pathology report containing patient name, block number, tissue collection date, and source of the tissue must accompany the specimen for testing to be performed.

Limitations

The test cannot differentiate between somatic and germline alterations. It does not detect multi-exon deletions, duplications, larger-scale genomic copy number variants, or epigenetic modifications. Detailed interpretation should consider clinical and histopathological data. Inadequate specimen collection may lead to inconclusive results. Variants detected below 5% mutant allele frequency may not be reliably identified, and rare polymorphisms could lead to erroneous results. This assay requires a minimum of 20% tumor content, and any misinterpreted results should be discussed with the laboratory.

Test Details

New York Approved