The Oncomine™ Precision Assay Liquid Biopsy

June 2023
Ampath | ampath.co.za

Introduction

Ampath now offers the Oncomine™ Precision Assay Liquid Biopsy (LBPA), a cutting-edge test for comprehensive analysis of solid tumour malignancies using cell-free DNA from blood samples.

Platform:

• Performed on the Ion Torrent Genexus system
• Detects the same variants and fusions as the tissue-based OPANGS (Oncomine™ Precision Assay – FFPE)

This test complements, but does not replace, the existing EGFR T790M liquid biopsy (LBEGFR).

Comparison: LBPA vs LBEGFR

✅ Oncomine™ Precision Assay Liquid Biopsy (LBPA)

• Mnemonic: LBPA
• Specimen: Blood (cell-free DNA, 10 mL)
• Container: Streck tube (camouflage-top glass)
• Transport: Room temperature to NRL ASAP
• Turnaround: ~10 working days
• Indications:
  • Applicable to all patients with histologically confirmed malignancy
  • Used to identify treatable or treatment-resistant mutations

✅ EGFR T790M Liquid Biopsy (LBEGFR)

• Mnemonic: LBEGFR
• Specimen: Blood (cell-free DNA, 10 mL)
• Container: Streck tube
• Transport: Room temperature to NRL ASAP
• Turnaround: ~10 working days
• Indications:
  • Used in non-small cell lung carcinoma (NSCLC)
  • Detects the EGFR T790M mutation, which is associated with resistance to treatment

Advantages of Liquid Biopsy

• Minimally invasive
• Enables monitoring of tumour evolution
• Can detect resistance mutations like EGFR T790M
• Allows repeated testing over time
• May reduce overall costs compared to tissue biopsy (no surgery, anaesthesia, hospitalisation, etc.)
• Offers insight into intra-tumour genetic heterogeneity

Additional Advantages of LBPA

• Higher sensitivity:
  • EGFR mutations detectable at 0.05% frequency (vs 5% with T790M testing)
• Broad panel testing:
  • Covers 50 DNA/RNA genes
  • Detects additional targetable and resistance mutations
• Fusion detection (via RNA panel):
  • Identifies rearrangements in:
    • ALK
    • ROS
    • RET
    • MET
    • NTRK

📌 Note: Liquid biopsy is a complementary test, not a replacement for histological diagnosis. Tissue remains the gold standard for initial diagnosis.

📧 For more information, contact the NGS Laboratory at:
ngs@ampath.co.za

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