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Programmed death ligand 1 expression in EBUS aspirates of non–small cell lung cancer: Is interpretation affected by type of fixation?
Author(s) -
Gosney John R.,
Haragan Alexander,
Chadwick Claire,
Giles Tom E.,
Grundy Seamus,
Tippett Victoria,
Gumparthy Krishna P.,
Wight Andrew,
Tan Hock G.
Publication year - 2020
Publication title -
cancer cytopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.29
H-Index - 57
eISSN - 1934-6638
pISSN - 1934-662X
DOI - 10.1002/cncy.22216
Subject(s) - fixative , medicine , lung cancer , fixation (population genetics) , lymph node , cytology , pathology , immunohistochemistry , histology , cancer , oncology , staining , population , environmental health
Background Much of the reluctance about using cytology specimens rather than histology specimens to assess programmed death ligand 1 (PD‐L1) expression for guiding the use of immune modulating drugs in the management of non–small cell lung cancer (NSCLC) is based on the belief that the alcohol‐based fixatives favored by cytopathologists might reduce the antigenicity of PD‐L1 and lead to artifactually low expression levels and false‐negative reporting. Therefore, this study was performed to determine whether there is any difference in PD‐L1 expression between endobronchial ultrasound (EBUS)–guided aspirates of NSCLC fixed in alcohol‐based fixatives and those fixed in neutral buffered formalin (NBF), the standard laboratory fixative for histology specimens. Methods The expression of PD‐L1 was compared in 50 paired EBUS aspirates of NSCLC taken from the same lymph node during the same procedure. One aspirate of each pair was fixed in an alcohol‐based fixative, and the other was fixed in NBF. Results In none of the 50 pairs was there any significant difference, qualitative or quantitative, in the strength, pattern, or extent of PD‐L1 expression. In the great majority, the expression was identical, regardless of fixation. Conclusions There is no evidence from this study showing that the use of alcohol‐based fixatives has any effect on the expression of PD‐L1 or its interpretation. Notwithstanding the general challenges in accurately assessing such expression in cytology specimens, pathologists should feel able to interpret them with confidence, and clinicians should feel able to rely on the results.