4P - PD-L1 in NSCLC cytology

Date 07 May 2017
Event ELCC 2017
Session Poster Display Session
Topics Thoracic Malignancies
Pathology/Molecular Biology
Non-Small Cell Lung Cancer
Basic Scientific Principles
Presenter Mile Kovacevic
Citation Annals of Oncology (2017) 28 (suppl_2): ii1-ii5. 10.1093/annonc/mdx090
Authors M. Kovacevic1, I. Kern2, S. Gabrič2
  • 1Cytology And Pathology Laboratory, University Clinic Golnik, 4204 - Golnik/SI
  • 2University Clinic Golnik, Golnik/SI



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.