Title

Diagnostic utility of BAP1 for malignant pleural mesothelioma in pleural fluid specimens with atypical morphology

Document Type

Journal Article

Publication Title

Cytopathology

Volume

33

Issue

1

First Page

84

Last Page

92

PubMed ID

34033161

Publisher

Wiley

School

School of Medical and Health Sciences

RAS ID

38868

Funders

iCARE Dust Disease Board PhD Scholarship

Comments

Louw, A., Lee, Y. C. G., Acott, N., Creaney, J., van Vliet, C., & Chai, S. M. (2022). Diagnostic utility of BAP1 for malignant pleural mesothelioma in pleural fluid specimens with atypical morphology. Cytopathology, 33(1), 84-92.

https://doi.org/10.1111/cyt.13015

Abstract

Objective:

To assess the utility of BRCA1-associated protein 1 (BAP1) immunohistochemistry (IHC) for the diagnosis of malignant pleural mesothelioma (MPM) in fluid samples with atypical cytology.

Methods:

Pleural fluid samples with an atypical mesothelial proliferation (diagnostic categories: ‘atypical’ and ‘suspicious’) received between January 2015 and March 2018 at a tertiary referral centre were identified. Results of routine IHC testing were recorded for each case. BAP1 by IHC was performed and a final diagnosis sought from subsequent pathology specimens, medical records, or consensus clinical diagnosis.

Results:

Of 50 cases identified, 41 were reported as atypical and 9 as suspicious. Seven (14%) demonstrated loss of BAP1 staining, 40 retained BAP1 staining, 1 had heterogeneous staining, and 2 had insufficient cells for analysis. All seven cases with BAP1 loss were diagnosed with MPM on follow-up. Of those with retained BAP1, 52.5% (21) were subsequently diagnosed with MPM, while 40% (16) had non-MPM diagnoses after a median follow-up of 24 months. Three cases were not further investigated based on patient and clinician decision. The case with heterogeneous staining was diagnosed as mesothelioma by clinical consensus.

Conclusions:

BAP1 IHC loss is highly specific for malignancy and has value as a rule-in test. Even in a tertiary centre with clinical interest in the cytological diagnosis of MPM this investigation was able to increase diagnostic accuracy beyond routine IHC studies. Cytological criteria remain valuable, as retained BAP1 in an atypical or suspicious mesothelial proliferation cannot exclude malignancy.

DOI

10.1111/cyt.13015

Access Rights

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Research Themes

Health

Priority Areas

Multidisciplinary biological approaches to personalised disease diagnosis, prognosis and management

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