PIK3CA Mutation Analysis

Test Code

16897

CPT Codes
81309

Preferred Specimen

Formalin-fixed, paraffin-embedded tissue

Minimum Volume

3 mL whole blood • 1 mL bone marrow aspirate • 4 unstained charged (+) slides

Other Acceptable Specimens

5 mL whole blood collected in an EDTA (lavender-top) tube or sodium heparin (green-top) tube • 3 mL bone marrow aspirate collected in an EDTA (lavender-top) tube or sodium heparin (green-top) tube • 8 unstained charged (+) slides

Instructions

Do not reject specimens, send to laboratory for screening

Paraffin block is the preferred sample type. Sample source and block ID are required on the requisition form and a pathology report must be submitted.
Whole Blood (acceptable): Follow standard whole blood collection procedures. Collect 3-5 mL whole blood in an EDTA tube. Record sample type, collection time, and date on both tube and requisition form.
For bone marrow (acceptable) collection, the notation of sample type, collection time, and date on the tube and requisition form is required. Ship sample at refrigerated temperature or room temperature. Ship immediately to maintain stability.

Transport Temperature

FFPE and slides: Room temperature
Whole blood and bone marrow: Refrigerated (cold packs)

Specimen Stability

FFPE tissue/slides
Room temperature: 5 years
Refrigerated: 5 years
Frozen: Unacceptable

Whole blood, bone marrow
Room temperature: 72 hours
Refrigerated: 72 hours
Frozen: Unacceptable

Methodology
Next Generation Sequencing

FDA Status
This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by FDA. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.

Setup Schedule

Monday-Sunday Morning
Report available: 7 Days

Reference Range

Not detected

Clinical Significance

Phosphoinositide 3-kinase (PI3K) is a lipid kinase responsible for the generation of an important signaling second messenger involved in cell survival and proliferation. The most highly expressed catalytic subunit, p110alpha, is encoded by the PIK3CA gene (Ch3q26.32). PIK3CA has been shown to be mutated in a high percentage of human cancer (10-15% overall), including endometrial (36%), breast (27%), and colorectal cancers (23%).

Mutational hotspots in PIK3CA include exons 1, 9 and 20. Mutations in these regions have been reported to be associated with poor outcome in each of these malignancies and may provide patient stratification in breast cancers. In addition, mutations in PIK3CA correlate with resistance to cetuximab therapy in colorectal cancer patients. PIK3CA mutation status may therefore provide prognostic information for a number of solid tumors, as well as aid in the improvement of molecular stratification of patients.

PIK3CA mutation status, especially in combination with other molecular tests, will also be an important consideration in the design of therapeutic strategies for certain malignancies. This test covers greater than 95% of the reported mutations in PIK3CA.

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.