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HelpTest ID: PIK3B Cell-Free DNA PIK3CA Test, Blood
Shipping Instructions
1. Samples should be transported at ambient temperature or refrigerated (4° C)
2. Samples are viable for 7 days in the Streck Black/Tan Top Tube Kit
Specimen Required
Supplies: Streck Black/Tan Top Tube Kit (T715)
Specimen Volume: Two, 10-mL Streck cell-free DNA (cfDNA) blood collection tubes
Additional Information:
1. Only blood collected in Streck cfDNA tubes will be accepted for analysis.
2. Whole blood will be processed to produce platelet-poor plasma before cfDNA isolation.
Useful For
Identification of hormone receptor positive and human epidermal growth factor receptor 2 negative (HR+/HER2-) advanced breast cancer tumors that may be eligible for treatment with targeted kinase inhibitor therapy (eg, alpelisib).
Method Name
Polymerase Chain Reaction (PCR)
Reporting Name
cfDNA PIK3CA Test, BloodSpecimen Type
Whole bloodSpecimen Minimum Volume
One 10 mL Streck cell-free DNA tube
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Whole blood | Ambient (preferred) | 7 days | Streck Black/Tan top |
| Refrigerated | 7 days | Streck Black/Tan top |
Clinical Information
More than 70% of breast cancers are hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative (HR+/HER2-). Approximately 40% of patients with HR+/HER2- advanced breast cancer have activating mutations in the gene PIK3CA, inducing hyperactivation of the alpha isoform (p110 alpha) of phosphatidylinositol 3-kinase, a key upstream component of the PI3K pathway. Mutations in PIK3CA are associated with tumor growth, resistance to endocrine therapy, and a poor overall prognosis.
Patients with HR+/HER2- advanced breast cancer identified to have a PIK3CA mutation may be eligible for treatment with targeted kinase inhibitor therapy (eg, alpelisib).
This test uses circulating tumor DNA extracted from blood to evaluate for the presence of 10 clinically actionable PIK3CA mutations:
E542K (c.1624G>A)
E542K (c.1633G>A)
E545D (c.1635G>T)
E545G (c.1634A>G)
E545A (c.1634A>C)
H1047Y (c.3139C>T)
C420R (c.1285C>T)
Q546E (c.1636C>G)
H1047L (c.3140A>T)
H1047R (c.3140A>G)
Reference Values
An interpretive report will be provided
Interpretation
The interpretation of molecular biomarker results includes an overview of the results and the associated diagnostic, prognostic, and therapeutic implications.
Clinical Reference
1. Bachman KE, Argani P, Samuels Y, et al: The PIK3CA gene is mutated with high frequency in human breast cancers. Cancer Biol Ther. 2004 Aug;3(8):772-775
2. Andre F, Ciruelos E, Rubovszky G, et al: Alpelisib for PIK3CA-mutated, hormone receptor-positive advanced breast cancer. N Engl J Med. 2019 May 16;380(20):1929-1940
3. Andre F, Ciruelos EM, Juric D, et al: Alpelisib plus fulvestrant for PIK3CA-mutated, hormone receptor-positive, human epidermal growth factor receptor-2-negative advanced breast cancer: final overall survival results from SOLAR-1. Ann Oncol. 2021 Feb;32(2):208-217
Day(s) Performed
Monday through Friday
Report Available
5 to 10 daysTest Classification
This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
81309
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| PIK3B | cfDNA PIK3CA Test, Blood | 60034-6 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 616647 | Result Summary | 50397-9 |
| 616648 | Result | 82939-0 |
| 616649 | Interpretation | 69047-9 |
| 616650 | Additional Info | 48767-8 |
| 616651 | Specimen | 31208-2 |
| 616652 | Source | 31208-2 |
| 616653 | Released By | 18771-6 |
Forms
If not ordering electronically, complete, print, and send an Oncology Test Request (T729) with the specimen.
mcl-oncology; mcl-moltechtestmenu; mcl-oncology