EGFR gene status in cytological samples of nonsmall cell lung carcinoma

Controversies and opportunities

Authors

  • Gilda da Cunha Santos PhD, MD, FRCPC,

    Corresponding author
    1. Department of Laboratory Medicine and Pathobiology, University of Toronto, Ontario, Canada
    2. Laboratory Medicine Program, University Health Network, Toronto, Ontario, Canada
    • Department of Laboratory Medicine and Pathobiology, University of Toronto, University Health Network, 200 Elizabeth Street, 11th Floor, Eaton Wing, Toronto, Ontario M5G 2C4
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    • Fax: (416) 340-5517

  • Mauro Ajaj Saieg MD, PhD,

    1. Department of Laboratory Medicine and Pathobiology, University of Toronto, Ontario, Canada
    2. Laboratory Medicine Program, University Health Network, Toronto, Ontario, Canada
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  • William Geddie MD, FRCPC,

    1. Department of Laboratory Medicine and Pathobiology, University of Toronto, Ontario, Canada
    2. Laboratory Medicine Program, University Health Network, Toronto, Ontario, Canada
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  • Natasha Leighl MD, FRCPC

    1. Department of Laboratory Medicine and Pathobiology, University of Toronto, Ontario, Canada
    2. Laboratory Medicine Program, University Health Network, Toronto, Ontario, Canada
    3. Department of Medical Oncology, University Health Network, Toronto, Ontario, Canada
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  • We thank the University Health Network Molecular Diagnostics Laboratory for providing the photographs from the mutation assays.

Abstract

BACKGROUND:

In nonsmall cell lung cancer (NSCLC), the development and clinical application of tyrosine kinase inhibitors (TKIs) targeting the epidermal growth factor receptor (EGFR) has required the investigation of EGFR status by gene copy number and/or mutation analysis. This review aimed to present the current knowledge of the use of cytological specimens for EGFR testing in lung cancer.

METHODS:

A systematic computerized search was performed of the MEDLINE(R) and EMBASE databases to identify articles reporting the use of cytological samples for determining EGFR status in NSCLC.

RESULTS:

Data were extracted from 30 original articles. An additional 19 reviews, consensus statements, and editorials were selected from 175 retrieved papers. Different techniques using cell blocks, scraped cells from archival slides, and fresh cells have shown promising results and include fluorescent in situ hybridization (FISH), direct sequencing, and quantitative polymerase chain reaction (PCR), with similar or higher accuracy and sensitivity than surgical specimens. Preservation and quality of the extracted DNA seem to matter more than the actual number of tumor cells present in the samples. However, major issues still reside in the amount of material, the interference from background non-neoplastic cells, and standardization of parameters for cytological samples.

CONCLUSIONS:

This analysis provided evidence that cytological material is suitable for detecting EGFR status using several different methodologies and preparations. New prospective, clinical studies are encouraged for collection and handling of cytological samples as well as for validation of novel techniques in large cohorts. Cancer (Cancer Cytopathol) 2011;. © 2011 American Cancer Society.

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