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Cell‐blocks are suitable material for programmed cell death ligand‐1 immunohistochemistry: Comparison of cell‐blocks and matched surgical resection specimens in lung cancer
Author(s) -
Pak Min Gyoung,
Roh Mee Sook
Publication year - 2019
Publication title -
cytopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 48
eISSN - 1365-2303
pISSN - 0956-5507
DOI - 10.1111/cyt.12743
Subject(s) - concordance , medicine , lung cancer , cytology , immunohistochemistry , biomarker , pd l1 , cancer , pathological , immunotherapy , pathology , oncology , biology , biochemistry
Objective Programmed cell death ligand‐1 ( PD ‐L1) has emerged as a predictive biomarker in lung cancer. PD ‐L1 immunohistochemistry ( IHC ) assay predicts the response to immunotherapy, but cytology specimens are often the only samples available in a considerable proportion of advanced lung cancer patients. We delineate practical feasibility and efficacy of cytology cell‐block ( CB ) specimens for PD ‐L1 expression and concordance between cytology CB s and surgical resection specimens. Methods In total, 58 eligible patients with primary lung cancer who received computed tomography‐guided percutaneous needle aspiration and surgery were included. PD ‐L1 IHC (clone SP 263) was performed on CB s prepared from residual liquid‐based cytology material and matched surgical resection specimens. PD ‐L1 positive tumour cell proportion was categorised in four score groups: (a) <1%; (b) ≤1% to <10%; (c) ≤10% to <50%, (d) ≥50%. Results Comparison of PD ‐L1 expression in cytology CB s and matched surgical resection specimens showed a high concordance (κ value 0.65). According to the therapeutic guideline of immunotherapeutic agents, a positive percent agreement was 94.34%, and a negative percent agreement was 100% at a cut‐off value for positivity of 1% PD ‐L1 expression. There was a significant difference observed with regard to rates of PD ‐L1 positivity when comparing smoking history ( P = 0.02), age ( P = 0.04) and pathological TNM stage ( P = 0.04). Conclusions The results show that cytology CB s evaluated for PD ‐L1 IHC assay have high concordance with matched surgical resection specimens and can be used for assessing PD ‐L1 expression. Also, we propose that CB s are suitable materials for evaluating PD ‐L1 expression while simultaneously performing both diagnostic and molecular tests.