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  P2.01 - Advanced NSCLC (Not CME Accredited Session) (ID 950)

  • 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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    P2.01-75 - Study of Molecular Alterations in Cytological Smears By FISH In Patients with Advanced Non Small Cell Lung Carcinoma (NSCLC). (ID 11298)

    16:45 - 18:00  |  Author(s): Paola Ximena De La Iglesia Niveyro.
    • Abstract
    • Slides

    Background
    

    Lung cancer represents one of the leading causes of cancer mortality worldwide. In most cases, its diagnosis is made at an advanced stage of the disease when patients are no longer candidates for surgical resection of the primary tumor. In these cases, small biopsies and cytological samples obtained through minimally invasive procedures, often represent the only chance of obtaining diagnostic material. This includes molecular study which increasingly incorporates more genes of interest into the diagnostic routine to define therapeutic approach. At the Pathology Department of the Hospital Italiano de Buenos Aires, the study of ALK, ROS1 and more recently, the study of MET, is performed on paraffin samples by immunohistochemistry (IHC) or by fluorescence in situ hybridization (FISH).

    Aims: To incorporate the use of FISH on cytological material within the practices of our department.

    a9ded1e5ce5d75814730bb4caaf49419 Method
    

    We collected cytological smears of 1) lung nodule or lung cancer metastases needle biopsies from patients with non-surgical stage disease (n=10); 2) imprinted cytological samples from positive mediastinoscopies during the intraoperative staging of patients with lung cancer (n=11); 3) positive pleural fluid in patients with pulmonary nodule (n=2). Then we performed FISH technique, evaluated the quality of the signal obtained, and compared the results with those obtained on paraffin sections. FISH technique on paraffin blocks was performed using 2XSSC/ proteinase K pretreatment as standardized by our lab. Cytology smears were destained and fixed in 10% methanol and incubated with FISH probe (ALK, ROS1 and MET).

    4c3880bb027f159e801041b1021e88e8 Result
    

    All cytology cases had scorable signals and were easy to interpret. Also, as no pretreatment was required, assay time was shorter. Depending on cellularity, one same slide was useful for analysis of the three probes.

    When comparing with IHC and FISH studies, we obtained a 100% correlation with ALK (n=23; positive=2, negative=21), ROS1 (n=5, all negative) and MET (n=5, all negative).

    8eea62084ca7e541d918e823422bd82e Conclusion
    

    This work allowed us to optimize the use of different cytology samples frequently available in advance stage NSCLC for FISH studies. The use of cytological material might improve turnaround time for results and can become a useful tool in pathology labs, in particular when paraffin included material is limited.

    6f8b794f3246b0c1e1780bb4d4d5dc53

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