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I. Kern

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    Poster Display Session (ID 63)

    • Event: ELCC 2017
    • Type: Poster Display Session
    • Track:
    • Presentations: 1
    • Moderators:
    • Coordinates: 5/07/2017, 12:30 - 13:00, Hall 1
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      4P - PD-L1 in NSCLC cytology (ID 446)

      12:30 - 13:00  |  Author(s): I. Kern

      • Abstract

      PD-L1 is a predictive biomarker for NSCLC, which is determined by immunohistochemistry. Significant number of NSCLCs are diagnosed from cytology samples. No study of PD-L1 expression in NSCLC cytology samples was published to date. The aim of this study was to evaluate possiblity of immunocytochemical determination of PD-L1 status in primary and metastatic NSCLC.

      We examined 50 consecutive cytology samples from 50 patients (19 TBNAs of mediastinal lymph nodes, 9 FNABs of peripheral lymph nodes, 15 TBNAs of lung, 4 pleural effusions, 2 FNABs of subcutaneous mass and one US – guided FNAB of liver). Methanol – fixed cytospins were prepared for immunocytochemistry using PD-L1 mouse monoclonal antibody (clone 22C3, Dako, USA) on an automated staining platform (Benchmark, Ventana/Roche, USA). Samples containing 100 or more tumor cells were considered representative. PD-L1 expression was evaluated on tumor cells with membranous staining. PD-L1 positivity was defined by cutoff value of 1%. 18 patients had concurrent histology samples used for PD-L1 immunohistochemistry (FFPE sections, same PD-L1 antibody clone and platform).

      We found 37 (74%) adenocarcinomas, 7 (14%) squamous cell carcinomas, while 6 (12%) remained NSCLC-NOS. 74% of all NSCLC samples showed positive immunocytochemical reaction with PD-L1. 27 (73%) of all adenocarcinomas, 4 (57%) of all squamous cell carcinomas and 6 (100%) of all NSCLC-NOS showed positive immunocytochemical reaction with PD-L1. In patients with both cytology and histology samples, concordance in PD-L1 expression was 78%. All types of cytology samples examined in the study showed to be representative for evaluation. Most problems occurred in evaluation of pleural effusion due to nonspecific cytoplasmic staining for PD-L1 in histiocytes.

      Cytology samples are adequate for evaluation of PD-L1 expression in primary and metastatic NSCLC.

      Clinical trial identification:

      Legal entity responsible for the study:
      University Clinic Golnik

      University Clinic Golnik

      All authors have declared no conflicts of interest.