Author of

• 18972

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  P2.02 - Biology/Pathology (ID 616)

  • Event: WCLC 2017
  • Type: Poster Session with Presenters Present
  • Track: Biology/Pathology
  • Presentations: 1
  • Moderators:
  • Coordinates: 10/17/2017, 09:30 - 16:00, Exhibit Hall (Hall B + C)

  • 23243

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    P2.02-045 - PD-L1 Assessment in Cytology Samples (ID 10485)

    09:30 - 09:30  |  Author(s): A. Lerner
    • Abstract

    Background:
    Pembrolizumab therapy for non-small cell lung cancer requires patient selection using PD-L1 immunohistochemistry (IHC). FDA approval was based on staining of resections or core biopsies. There is only limited data on PD-L1 expression in fine needle aspiration (FNA) specimens including EBUS of mediastinal lymph nodes.
    
    Method:
    Immunohistochemistry (IHC) was performed on an automated platform (Ventana Benchmark Ultra) using clone 22C3 (Dako) and the Optiview detection system (Ventana Medical Systems) on formalin fixed paraffin embedded FNA cell blocks (n:49), cell blocks from aspirated fluids (n:14), core biopsies (n:21) and 4 transbronchial biopsies. The cohort included of 18 squamous cell carcinomas, 56 adenocarcinomas (ACA), 2 adenosquamous carcinoma, 1 NUT-1 carcinoma, 7 NSCLC and 2 melanomas (age: 24-89, mean: 66, median: 69; 43 female and 45 male). Membranous PD-L1 staining of any intensity and extent was recorded in at least 100 tumor cells (tumor proportion score). The tumors were grouped as: no staining (< 1%), low expression (1-49%) and high expression (50% or more).
    
    Result:
    Twenty (23.3%) tumors showed no staining, 26 (30.2%) low expression and 40 (46.5%) high expression. Of the 56 adenocarcinomas 21 (37.5%) showed high expression, while of the 18 squamous cell carcinomas 7 (39%) showed high PD-L1 expression. The other tumors with high expression included one adenosqaumous carcinoma and 11 poorly differentiated carcinomas. One EBUS biopsy also had PDL1 assessed on a transbronchial biopsy of the primary tumor showing similar staining (30% versus 20%).
    
    Conclusion:
    PD-L1 immunohistochemistry appears to be feasible using formalin fixed cell blocks of fine needle aspirates and aspirated fluid specimens containing adequate number of viable tumor cells. High PD-L1 expression was seen in approximately half the tumors, which is greater than has been observed in resections/core biopsies, this finding merits further study. High expression of PD-L1 was seen in both squamous cell carcinoma and adenocarcinomas.