Author of

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  P1.02 - Poster Session with Presenters Present (ID 454)

  • Event: WCLC 2016
  • Type: Poster Presenters Present
  • Track: Biology/Pathology
  • Presentations: 1
  • Moderators:
  • Coordinates: 12/05/2016, 14:30 - 15:45, Hall B (Poster Area)

  • 16576

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    P1.02-027 - A Comparative Analysis of Different Cytological Samples for the Assessment of ALK Gene Rearrangements in NSCLC Patients (ID 5160)

    14:30 - 14:30  |  Author(s): M. Aguirre
    • Abstract
    • Slides

    Background:
    Determination of ALK gene rearrangements has been traditionally performed in biopsies and/or surgical specimens. However, advanced lung cancer is often diagnosed by FNA cytology obtained through minimally invasive procedures, and frequently cytological specimens are the only samples available, thus emphasizing the necessity to expand ALK analysis to cytologic specimens. We assessed the feasibility of determining ALK gene rearrangements in different types of cytological samples.
    
    Methods:
    We studied prospectively 268 cytological samples from 268 NSCLC patients for ALK gene rearrangements by FISH (Vysis LSI ALK Dual Color Break Apart and ZytoLight SPEC ALK Dual Color Break Apart). Tumour samples were obtained by bronchoscopy -FNA in 45 cases (19.79%), EBUS-FNA in 63 (23.50%), EUS-FNA in 56 (20.89%), CT-FNA in 28 (10.44%), Ultrasonography guided-FNA in 24 (8.95%), and direct FNA in 23 cases (8.58%). Two cavity fluids (0.74%), 4 imprints from surgical specimens (1.49%), and 22 cases received for consultation (8.20%) were also studied. ROSE was done in all FNA procedures. FISH was performed on stained smears in 133 cases (49.62%) (114 Papanicolau and 19 Diff-Quick), ThinPrep in 48 (17.91%), SurePath in 12 (4.47%), and cell block in 75 cases (27.98%). All cases were tested for EGFR and KRAS mutations.
    
    Results:
    Two hundred thirty five samples (87.68%) were adequate for FISH analysis. Fifteen cases (5.59%) had ALK gene rearrangements. One case had a concurrent EGFR mutation in exon 21 plus the T789M mutation, and two had also KRAS mutations (G12D and G12C respectively). FISH study was unsuccessful in 33 cases (12.31%): 8 from stained smears (6.01%), 12 from ThinPrep (25%), 8 from SurePath (66.66%), and 5 from cell blocks (6.66%). Correlation cytological / paraffin embedded samples was performed in 10 cases with a concordance rate of 100%.
    
    Conclusion:
    ALK gene rearrangements may be definitely detected in cytological samples and particularly in direct smears. Both, Papanicolau and Diff-Quick smears are suitable samples for FISH analysis. The nuclei on cytology smears are not truncated, which allows for the detection of the true number of FISH signals in a nucleus. It is mandatory an exquisite management and care of the samples to preserve quality. Coexistence of ALK gene rearrangements and EGFR and KRAS mutations were observed in one and two cases respectively, indicating that such alterations are not necessarily mutually exclusive
    
    

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