Lung Cancer Molecular Biomarkers
Mutation in epidermal growth factor receptor (EGFR) occurs in ~35% of non-small cell lung cancer (NSCLC) patients of East Asian origin and ~16% in Western populations1,2. Multiple in-frame deletions in exon 19 and the p.L858R missense mutation in exon 21 comprise 90% of the mutations detected3.
Studies have confirmed EGFR mutations as a predictive biomarker of treatment response to tyrosine kinase inhibitors (TKIs), Gefitinib and Erlotinib4,5. As such screening for EGFR mutations in NSCLC patients is deemed necessary before offering these drugs.
Most of the patients who initially responded to Gefitinib and Erlotinib will eventually develop resistance to the drugs. Recently, a third-generation EGFR TKI, which is effective in tumours harbouring the p.T790M EGFR mutation (~50–60% of lung cancer patients6,7,8), was approved in Australia for patients with NSCLC harbouring the EGFR T790M mutation following progression on an EGFR TKI9.
In line with the above, a new Medicare item was recently introduced (Item 73351) to test tumour tissue that is derived from a new sample from a patient with locally advanced (Stage IIIb) or metastatic (Stage IV) NSCLC, who has progressed on or after treatment with an EGFR TKI. The test is to be requested to determine the eligibility for accessing “Osimertinib” under the Pharmaceutical Benefits Scheme (PBS) criteria.
Lung cancer therapy continues to follow the genomic testing paradigm. New guidelines recommend ROS1 and PD-L1 testing for all patients with NSCLC at baseline before treatment.
In NSCLC patients, accurate detection of both KRAS and BRAF mutations is therefore of high clinical importance for therapy selection10,11.
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Somatic Mutation: Solid Tissue Molecular Profiling in Lung Cancer
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Aspect ctDNA Liquid Biopsy in Lung Cancer
References
- Mok TS et al., (2009) N Engl J Med 361(10):947–957.
- Rosell R et al., (2009) N Engl J Med 361(10):958–967.
- Pao W Miller VA. (2005) J Clin Oncol 23:2556-2568.
- Yang CH et al., (2008) J Clin Oncol 26(16):2745–2753.
- Sequist LV et al., (2008) J Clin Oncol 26(15):2442–2449 .
- Thress K et al., (2015) Lung Cancer 90:509–515.
- Wu Y et al., (2017) Br J Cancer 116:175–185.
- Yu H et al., (2013) Clin Cancer Res 19:2240–2247.
- AstraZeneca. (2016) TAGRISSO (osimertinib mesilate) product information.
- Linardou H et al., (2008) Lancet Oncol 9:962–972.
- Ohashi K et al., (2012) Proc Natl Acad Sci USA 109:E2127–2133.
- Chao M & Gibbs P (2009) J Clin Oncol 27:e279–e280.
- Haselmann V et al., (2018) Clinical Chemistry 64 (5):830–842.