EGFRmutation testing in lung cancer: a review of available methods and their use for analysis of tumour tissue and cytology samples

Abstract

AimsActivating mutations in the gene encoding epidermal growth factor receptor (EGFR) can confer sensitivity to EGFR tyrosine kinase inhibitors such as gefitinib in patients with advanced non-small-cell lung cancer. Testing for mutations in EGFR is therefore an important step in the treatment-decision pathway. We reviewed reported methods for EGFR mutation testing in patients with lung cancer, initially focusing on studies involving standard tumour tissue samples. We also evaluated data on the use of cytology samples in order to determine their suitability for EGFR mutation analysis.MethodsWe searched the MEDLINE database for studies reporting on EGFR mutation testing methods in patients with lung cancer.ResultsVarious methods have been investigated as potential alternatives to the historical standard for EGFR mutation testing, direct DNA sequencing. Many of these are targeted methods that specifically detect the most common EGFR mutations. The development of targeted mutation testing methods and commercially available test kits has enabled sensitive, rapid and robust analysis of clinical samples. The use of screening methods, subsequent to sample micro dissection, has also ensured that identification of more rare, uncommon mutations is now feasible. Cytology samples including fine needle aspirate and pleural effusion can be used successfully to determine EGFR mutation status provided that sensitive testing methods are employed.ConclusionsSeveral different testing methods offer a more sensitive alternative to direct sequencing for the detection of common EGFR mutations. Evidence published to date suggests cytology samples are viable alternatives for mutation testing when tumour tissue samples are not available.

Analytical Validation of BRAF Mutation Testing from Circulating Free DNA Using the Amplification Refractory Mutation Testing System

“…A recent systematic review 28 identified by the literature search has indicated that numerous studies have been published showing excellent performance of smear preparations, such that this preference is no longer appropriate. It is incumbent upon any laboratory that tests cytopathology specimens to perform appropriate validation studies of these as separate sample types, distinct from tissue and blood samples.…”

446 Detection of EGFR and KRAS Mutation by Pyrosequencing Analysis in Cytologic Samples of Non-Small Cell Lung Cancer

“…The utility of cytology samples in detecting mutations in lung cancer have recently been increased and relatively widely investigated (8,(30)(31)(32). Cytology samples are especially useful in The present study showed that cytology specimens are comparable, or even better than non-cytology specimens, in detecting both EGFR and KRAS mutations.…”

Histopathological and molecular features of lung cancer

“…The discovery of cancer-related driver molecular abnormalities have led to the development of efficient targeted therapies. Recent advances in understanding of the complex biology of LC, particularly of the activation of oncogenes by EGFR, KRAS, BRAF, ERBB2 mutations, ALK, ROS1, RET translocations or MET, FGFR1 amplifications in some LCs, have led to discovery of new targeted therapies (1,2,(8)(9)(10)(11)(12)(13)(14) . For this reason, biopsy specimens should be analyzed not only for diagnostic studies, but also maximum amount of tissue should be reserved for molecular studies.…”

“…Subsequent to ligand-binding, EGFR receptors homo-and heterodimerize and induce autophosphorylation of the intracellular tyrosine kinase domain. Thereafter molecular cascade of events involving in growth, cell proliferation, differentiation, and survival are triggered (10)(11)(12)(13)(14)(15)(16) . Cetuximab, panitumumab, zalutumumab, nimotuzumab, and matuzumab are examples of monoclonal antibodies produced against EGFR receptors (14) .…”