The impact of different fixatives on immunostaining of lung adenocarcinomas in pleural effusion cell blocks.

Bibliographic Details
Title: The impact of different fixatives on immunostaining of lung adenocarcinomas in pleural effusion cell blocks.
Authors: Mansour, Mohammed S. I., Pettersson, Louise, Seidal, Tomas, Strömberg, Ulf, Mager, Ulrich, Ali, Lana, Kumbaric, Sana, Hejny, Kim, Taheri‐Eilagh, Fereshteh, Mufti, Joudy, Nakdali, Dawla, Brunnström, Hans
Source: Cancer Cytopathology; Sep2024, Vol. 132 Issue 9, p569-579, 11p
Abstract: Background: Cell blocks (CBs) are widely used for biomarker analyses such as immunostaining. Although immunohistochemistry on formalin‐fixed paraffin‐embedded tissues is standardized, there are multiple preparation methods and fixatives for cytology. Our objective was to investigate the effect of different common fixatives on the immunoreactivity of pleural effusion CBs with metastatic lung adenocarcinomas. Methods: This prospective study included 24 malignant pleural effusions from different patients with lung adenocarcinoma. From each case, four identical CBs were fixed in 10% neutral buffered formalin, PreservCyt, CytoLyt, and CytoRich Red (only 17 of the cases), respectively. Samples containing <100 malignant cells were excluded. All CBs were stained with thyroid transcription factor 1 (TTF‐1; clones 8G7G3/1 and SPT24), napsin A, claudin 4, CEA, CK7, and epithelial cell adhesion molecule (EpCAM; clones BS14, Ber‐Ep4, and MOC‐31). The fraction and intensity of stained cells were evaluated. Results: Of the investigated markers, a significant difference in staining proportion was seen for TTF‐1 clone 8G7G3/1 and EpCAM clone MOC‐31, especially with cases being negative in CytoLyt (33.3% and 83.3% positive, respectively) and PreservCyt (62.5% and 83.3%) whereas being positive in CytoRich Red (76.5% and 94.1%) and formalin (both 95.8%). A significantly weaker intensity of staining was seen for all alcohol‐based fixatives compared to formalin for TTF‐1 clone 8G7G3/1, napsin A, and EpCAM clone MOC‐31, whereas EpCAM clone Ber‐Ep4 was significantly weaker only in PreservCyt compared with formalin. Conclusions: Immunocytochemical expression and concordance with formalin‐fixed CBs differ depending on the used fixative as well as the antibody and clone, warranting investigation of the reliability of each biomarker for non–formalin‐fixed cytology. Four identical cell blocks from each of 24 malignant pleural effusions with lung adenocarcinoma were fixed using different fixatives. The impact on immunostaining was evaluated for nine antibodies, with a lower staining proportion for alcohol‐based fixatives compared to formalin for example TTF‐1 clone 8G7G3/1 and EpCAM clone MOC‐31. [ABSTRACT FROM AUTHOR]
Copyright of Cancer Cytopathology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
Database: Complementary Index
More Details
ISSN:1934662X
DOI:10.1002/cncy.22833
Published in:Cancer Cytopathology
Language:English