Introduction to Biomarker Testing in Lung Cancer

Identification of specific biomarkers in lung cancer cells allows differentiation between tumour types, and provides predictive and prognostic information.

Several biomarkers have been found to be predictive for therapeutic efficacy in lung cancer, including sensitising epidermal growth factor receptor (EGFR) mutations, anaplastic lymphoma kinase (ALK) gene fusions, ROS proto-oncogene 1 (ROS1) gene rearrangements, B-Raf proto-oncogene (BRAF) mutations and programmed cell death-ligand 1 (PD-L1) expression levels. KRAS mutations have been found to be prognostic markers of innate tumour aggressiveness.1

    Examples of clinically relevant biomarkers in lung cancer1,2

  • Mutations in the EGFR gene
  • Rearrangements in the ALK gene
  • Activating mutations in the KRAS gene
  • Amplification of the MET gene
  • Mutations in the ROS1 gene
  • Expression of PD-L1
  • Expression of HER2

ALK, anaplastic lymphoma kinase; EGFR, epidermal growth factor receptor; HER2, human epidermal growth factor receptor-2; KRAS, Kirsten rat sarcoma viral oncogene homologue; MET, mesenchymal-epithelial transition; PD-L1, programmed death-ligand 1; ROS1, ROS proto-oncogene 1

The presence of EGFR mutations is predictive for response to EGFR tyrosine kinase inhibitor (EGFR-TKI) therapy. ALK fusions and ROS1 rearrangements are predictive for response to ALK-TKI therapy, the BRAF V600E mutation is predictive for response to BRAF/MEK inhibitor therapy, and PD-1/PD-L1 expression levels may be predictive of response to immune checkpoint inhibitor therapy.1,3

It is recommended that patients with metastatic adenocarcinoma non-small cell lung cancer are tested for EGFR mutations, ALK fusions, ROS1 rearrangements, BRAF mutations and PD-L1 expression levels.1,3

Performing robust, reliable, high-quality biomarker testing is key to making informed treatment decisions for patients. Testing should be conducted in the shortest possible timeframe so that treatment decisions can be made quickly.