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PDGFRA Mutation Analysis in Gastrointestinal Stromal Tumors (GISTs)

CPT 81314; 88381
Synonyms
  • Tyrosine Kinase Inhibitor (TKI, Imatinib) Responsiveness

Test Details

Cancer Type

Gastrointestinal stromal tumor (GIST)

Technology Used

Molecular

Turnaround Time

10 - 14 days

Use

The platelet-derived growth factor receptor alpha (PDGFRA) gene encodes a cell surface tyrosine kinase receptor for members of the platelet-derived growth factor family. PDGFRA and c-KIT have approximately 35% homology. They both belong to the PDGFRA subfamily of receptor tyrosine kinases, which are involved in the regulation of cell growth, proliferation, adhesion, migration, differentiation, and apoptosis. Recently, the kinase inhibitor Avapritinib (AYVAKIT™) was approved for the treatment of adults with unresectable or metastatic gastrointestinal stromal tumor (GIST) harboring a platelet-derived growth factor receptor alpha (PDGFRA) exon 18 mutation, including PDGFRA D842V mutations.

Special Instructions

This assay currently is not available in New York state.

Please provide a copy of the pathology report, and direct any questions regarding this test to oncology customer service at 800-345-4363.

Limitations

Genomic DNA is purified from the specimen provided. Exons 10, 12, 14, and 18 of PDGFRA gene coding are subjected to PCR amplification and bidirectional sequencing in duplicate to identify sequence variations. This assay has a sensitivity to detect approximately 10% of cells containing the PDGFRA mutations in a background of nonmutant cells. This assay will not detect the mutation below the sensitivity of this assay.

This test was developed and its performance characteristics determined by LabCorp. It has not been cleared or approved by the Food and Drug Administration. The FDA has determined that such clearance or approval is not necessary.

Methodology

Polymerase chain reaction (PCR) and DNA sequencing

Specimen Requirements

Information on collection, storage, and volume

Specimen

Formalin-fixed, paraffin-embedded (FFPE) tissue or five unstained slides from a paraffin block in 10-μM sections and a matching H&E reference slide

Volume

Formalin-fixed, paraffin-embedded (FFPE) block or five unstained slides from paraffin block in 10-μM sections and a matching H&E reference slide

Minimum Volume

2mm x 2mm tumor area with greater than or equal to 50% tumor

Container

Slides or blocks

Storage Instructions

Maintain blocks and slides at room temperature.

Causes for Rejection

Tumor block containing insufficient tumor tissue or tumor fixed in a heavy metal fixative; broken or stained slides