Gastrointestinal Stromal Tumor Mutations

Also known as: GISTMUT

Clinical Use

Use

The test is used to detect activating mutations in KIT and PDGFRA genes associated with gastrointestinal stromal tumors (GISTs). Identifying these mutations helps predict the response to tyrosine kinase inhibitor (TKI) therapy, an important aspect of personalized treatment planning for patients diagnosed with GIST.

Special Instructions

Not provided.

Limitations

This test will not detect mutations in other locations within the KIT or PDGFRA genes, in other genes, or below the limit of detection. The test evaluates variants in tumor tissue only and cannot distinguish between somatic and germline variants. Some large insertion/deletion mutations greater than 60bp may not be detected. Tissue samples yielding less than 50ng may yield suboptimal results. The limit of detection is 5% mutant allele frequency for single nucleotide variants and multi-nucleotide variants smaller than 60bp.

Test Details

Methodology

NGS (Targeted)

Biomarkers

KIT, PDGFRA

Gene

SNV/Indel

Mutation • Categorical (e.g., Positive / Negative / Indeterminate)

Result Turnaround Time

10-12 days

Specimen

Tissue (FFPE)

Volume

Not provided

Minimum Volume

Not provided

Container

Tissue transport kit (ARUP supply #47808)

Collection Instructions

Formalin fix (10 percent neutral buffered formalin) and paraffin embed tissue. Transport block and/or slides in a tissue transport kit. Transport 8 unstained 5-micron slides for resections. Transport 15 unstained 5-micron slides for small biopsies.

Storage Instructions

Room temperature, also acceptable refrigerated.

Causes for Rejection

Less than 10 percent tumor. Specimens fixed in fixative other than 10 percent neutral buffered formalin. Decalcified specimens. FNA smears with less than 50 tumor cells.