Author of

• 20039

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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

  • 19785

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    4P - PD-L1 in NSCLC cytology (ID 446)

    12:30 - 13:00  |  Author(s): S. Gabrič
    • Abstract

    Background:
    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.
    
    Methods:
    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).
    
    Results:
    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.
    
    Conclusions:
    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
    
    Funding:
    University Clinic Golnik
    
    Disclosure:
    All authors have declared no conflicts of interest.