*If prior authorization is not submitted, test may be delayed.
Polymerase Chain Reaction (PCR) followed by DNA sequence analysis
PDGFRA gene mutations occur in approximately 30% of gastrointestinal stromal tumors (GISTs) that are wild type for KIT mutation, and in 7% of GISTs overall. PDGFRA and KIT mutations are mutually exclusive in GISTs. The vast majority of PDGFRA gene mutations involve exons 12 and 18, and invariably result in constitutive activation of the PDGFRA protein. The most common PDGFRA mutation, D842V, is associated with imatinib therapy resistance. This DNA sequencing test will detect mutations within exons 12 and 18 of the PDGFRA gene. The tested regions correspond to PDGFRA amino acids 552-585 (exon 12) and 826-848 (exon 18). Appropriate specimens include formalin fixed paraffin-embedded blocks, unstained paraffin sections on slides, and fresh/frozen tissue. The submitted specimen should contain an adequate proportion of tumor nuclei (>40%) to enable mutation detection.
Interpretive report provided.
A negative result does not rule out the presence of a rare PDGFRA mutation outside of the sequenced regions or a low level mutation below the sensitivity of detection (15% mutant allele). Specimens should contain an adequate proportion of neoplastic cells (>30%) to enable mutation detection.
3 - 10 days
- PDGFRA Mutation Exon 12
- PDGFRA Mutation Detection for Gastrointestinal Stromal Tumor
- PDGFRA Mutation Exon 18
- PDGFRA Mutation for GIST
A formalin-fixed, paraffin-embedded tissue block containing an area with a high percentage of neoplastic cells (for micro-/macro-dissection) is preferred. Unstained, UNBAKED slides (5-8, 10-micron slides; 10-15 if few neoplastic cells are present) with associated H&E stained slide are also acceptable. Decalcified tissue or other fixatives will be accepted and the assay attempted, however these may result in failed testing due to degraded nucleic acid. Both blocks and slides should be stored at room temperature.
By ordering this test the clinician acknowledges that informed consent has been obtained from the patient as required by applicable state or federal laws and the ordering clinician has authorization from the patient permitting MLabs to report the test results to the ordering clinician. Test includes microdissection billed as a separate additional charge. Test includes pathologist interpretation of results billed as a separate additional charge. This test is not available without interpretation.