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Anuradha Choughule



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    P2.09 - Pathology (Not CME Accredited Session) (ID 958)

    • Event: WCLC 2018
    • Type: Poster Viewing in the Exhibit Hall
    • Track:
    • Presentations: 1
    • Moderators:
    • Coordinates: 9/25/2018, 16:45 - 18:00, Exhibit Hall
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      P2.09-10 - qRT-PCR as an Efficient and Reliable Diagnostic Screening Approach for the Detection of EML4-ALK Fusion Gene in NSCLC Samples:  A Pilot Study (ID 13391)

      16:45 - 18:00  |  Presenting Author(s): Anuradha Choughule

      • Abstract

      Background

      ALK gene rearrangement occurs in 3-5% of NSCLC patients and provides an oncogenic driver in these tumors and generally responds to Crizotinib therapy. Identification of this EML4-ALK fusion gene requires a very sensitive and specific method. Both FISH and IHC are widely used in clinical laboratories for the detection of ALK rearrangements in NSCLC tumor samples. RT-PCR-based assays have not yet been as widely used as FISH and IHC for the detection of ALK rearrangements in NSCLC. Our Our aim is to review performance of RT-PCR assay in comparison with FISH and IHC for the detection of EML4-ALK in NSCLC

      a9ded1e5ce5d75814730bb4caaf49419 Method

      A total of 100 cases of EGFR wild type were selected and were performed by FISH, IHC and RT-PCR simultaneously.

      4c3880bb027f159e801041b1021e88e8 Result

      Out of 105 tumor FFPE samples of NSLC, 76 % of tumor samples were biopsies and cytology and 24% were resections of archival lung and brain metastasis. The RT-PCR test (diagnostic cut-off ∆ Ct of ≤ 8) was shown to be highly sensitive (100%) when compared to FISH and IHC. The overall specificity of the RT-PCR test for the detection of ALK in cases without full-length ALK expression was 94% in comparison to FISH. No significant association was observed between EML4-ALK fusion gene and clinical stage.

      8eea62084ca7e541d918e823422bd82e Conclusion

      In contrast to FISH (Vysis ALK Break Apart probe) testing, as per the WHO guidelines, today IHC (Ventana ALK (D5F3 FDA approved) method is well accepted for the detection of EML4-ALK. However, in our study using FISH and IHC or FISH alone in comparison to RT-PCR have demonstrated that RT-PCR has a high sensitivity and specificity. This test has also shown the rapid TAT and has advantage of doing with ease as compared to FISH and IHC and can be done on biopsy as well as on cytology samples with lower tumor content.

      Our result indicates that identification of the specific variant by RT-PCR based ALK assay can potentially be used as a reliable standalone diagnostic screening approach and cost effective test and, which may apparently become important in the future for predicting patient response to ALK inhibitors. NGS fusion panels as the sole platform for detecting ALK and other NSCLC biomarkers in a single test are attractive.

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