Genomic‐based ancillary assays offer improved diagnostic yield of effusion cytology with potential challenges in malignant pleural mesothelioma

Kinoshita, Yoshiaki; Hamasaki, Makoto; Matsumoto, Shinji; Yoshimura, Masayo; Sato, Ayuko; Tsujimura, Tohru; Kamei, Toshiaki; Kawahara, Katsunobu; Nabeshima, Kazuki

doi:10.1111/pin.12973

Cited by 9 publications

(21 citation statements)

References 49 publications

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“…Detection of CDKN2A deletion is important in routine practice as it effectively discriminates MPM from reactive mesothelial proliferations, and is associated with poor prognosis in MPM (3)(4)(5)(6). There are several approaches used to circumvent the false negative results in detecting chromosomal microdeletion, including use of smaller probes (as used in the present study), enhancement of FISH signals (13), multiple ligation-dependent probe amplification (MLPA) assay (11) and array comparative genomic hybridization (CGH) (10).…”

Section: Discussionmentioning

confidence: 99%

“…However, it is difficult to distinguish MPM from benign mesothelial proliferative disorders in routine practice due to overlaps in morphology (3). Thus, genomic-based ancillary assays, such as fluorescence in situ hybridization (FISH) to detect homozygous deletion (homo-d) of the 9p21 locus and immunohistochemistry (IHC) analysis to detect loss of BRCA1-associated protein 1 (BAP1) expression and methylthioadenosine phosphorylase [MTAP; the protein product of the MTAP gene located in the telomere side of cyclin-dependent kinase inhibitor 2A (CDKN2A) in the 9p21 locus (3)] proteins, are effective tools for detecting characteristic genetic abnormalities that are essential in the diagnosis of MPM (3,4).…”

Section: Introductionmentioning

confidence: 99%

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Short 57 kb CDKN2A FISH probe effectively detects short homozygous deletion of the 9p21 locus in malignant pleural mesothelioma

et al. 2021

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Homozygous deletion (homo-d) of the cyclin-dependent kinase inhibitor 2A (CDKN2A) gene is frequently found in malignant pleural mesothelioma (MPM). Fluorescence in situ hybridization (FISH) is commonly used to detect chromosomal deletion, and sometimes reveals more frequent heterozygous deletion (hetero-d) compared with homo-d. In clinical practice, such CDKN2A FISH results belong to the 'borderline' homo-d rate, which makes it difficult to definitively diagnose MPM. Microdeletion, [<200 kilobase (kb)], can induce a 'pseudo' hetero-d signal in FISH assays with long probes owing to redundant probe reactivity. Thus, the present study hypothesized that shorter FISH probes can effectively detect the small deletion status of the CDKN2A gene and increase homo-d rate in MPM, which has high hetero-d and low homo-d status. The present study aimed to evaluate the effectiveness of a shorter CDKN2A FISH probe in diagnosing MPM. CDKN2A FISH with either a 222 kb long probe (L-probe) or a 57 kb short probe (S-probe) was performed in four MPM cases with high hetero-d and low homo-d patterns. Furthermore, immunohistochemistry for methylthioadenosine phosphorylase (MTAP) and quantitative (q)PCR analyses were performed to confirm the microdeletion of the 9p21 locus. The results demonstrated that all four MPM cases retained MTAP protein expression. CDKN2A FISH with L-probe revealed high hetero-d (cases 1-4; 73.3, 37.1, 59.2 and 64.8%, respectively) and low homo-d (cases 1-4; 12.1, 12.4, 25.4 and 22.2%, respectively). CDKN2A FISH with S-probe revealed high homo-d (cases 1-4; 96.8, 90.0, 87.5 and 82.6%, respectively), with low hetero-d (cases 1-4; 0.0, 1.2, 1.2 and 4.3%, respectively). qPCR analysis demonstrated no allele deletions of the MTAP gene and two-allele deletions of the CDKN2A gene in 3/4 cases. Taken together, these results suggest that the S-probe detects the short homo-d of the 9p21 locus more effectively than the L-probe in MPM. This can assist in solving diagnostic difficulties in cases involving high hetero-d with low homo-d.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Short 57 kb CDKN2A FISH probe effectively detects short homozygous deletion of the 9p21 locus in malignant pleural mesothelioma

et al. 2021

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“…We analyzed cell blocks prepared from pleural effusions obtained from patients with MPM or RMC from the pleural lesion files of the Department of Pathology, Fukuoka University Hospital, which includes consultation cases, between the years 2010 and 2019. RMCs were defined as a reactive proliferation of mesothelial cells in association with several underlying conditions, including infection, pneumothorax, trauma, cardiovascular disease, or lung cancer 22 . All patients completed a detailed medical evaluation and radiologic assessment before the diagnosis of MPM or RMCs.…”

Section: Methodsmentioning

confidence: 99%

“…Nonmesothelial cells that were immunoreactive to BAP1 and MTAP (eg, inflammatory cells, including histiocytes and lymphocytes) served as internal positive controls in each staining protocol. BAP1 IHC revealed staining in the nucleus, and BAP1 loss in tumor cells was defined as complete nuclear loss 9,10,22 . Cytoplasmic reactivity to BAP1 was interpreted as a nonspecific reaction.…”

Section: Methodsmentioning

confidence: 99%

Fluorescence in situ hybridization detection of chromosome 22 monosomy in pleural effusion cytology for the diagnosis of mesothelioma

Kinoshita

Hamasaki

Matsumoto

et al. 2021

Cancer Cytopathology

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Background Malignant pleural mesothelioma (MPM) is characterized by mutations in several genes, including cyclin‐dependent kinase‐inhibitor 2A/p16 in the 9p21 locus, BRCA1‐associated protein 1 (BAP1), and neurofibromatosis type 2 (NF2) in the 22q12 locus. Recent studies indicate that fluorescence in situ hybridization (FISH) detects hemizygous loss of NF2 in tissue specimens of MPM. The authors investigated whether NF2 FISH, either alone or in combination with other diagnostic assays (9p21 FISH, methylthioadenosine phosphorylase [MTAP] immunohistochemistry [IHC], and BAP1 IHC), effectively distinguishes MPM cells from reactive mesothelial cells (RMCs) in cell blocks prepared from pleural effusions. Methods FISH assays were used to examine the deletion status of NF2 and 9p21, and IHC was used to determine the expression of MTAP and BAP1 in cell blocks from 54 cases with MPM and 18 cases with RMCs. Results Hemizygous NF2 loss (chromosome 22 monosomy or hemizygous deletion) showed 51.9% sensitivity (48.1% for chromosome 22 monosomy and 3.7% for hemizygous deletion) and 100% specificity in differentiating MPM cells from RMCs. Combinations of NF2 FISH, 9p21 FISH, and BAP1 IHC assays yielded greater sensitivity (98.1%) than any assay alone (9p21 FISH, 61.1%; MTAP IHC, 52.8%; or BAP1 IHC, 60.4%). The level of hemizygous NF2 loss in cell blocks positively correlated with that in corresponding tissues. Furthermore, to overcome cytologic specimen‐specific challenges, FISH combined with cytokeratin AE1/AE3 immunofluorescence was necessary in 25.9% of MPM cases for FISH assessment of predominantly scattered MPM cells. Conclusions NF2 FISH alone or in combination with other diagnostic assays effectively differentiates MPM cells from RMCs in cell blocks prepared from pleural effusions.

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“…Since then, more recent literature points toward high specificity for this marker, with highly variable sensitivity 43 . As reported by Churg et al, 43 several studies evaluating the performance of this ancillary test in cytology material all confirmed high specificity and variable sensitivity 47,66,67 . An unequivocal cutoff for HD definition has not been established 68 .…”

Section: Fish For P16 Homozygous Deletionmentioning

confidence: 97%

Diagnostic mesothelioma biomarkers in effusion cytology

Eccher¹,

Girolami

Lucenteforte

et al. 2021

Cancer Cytopathology

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Malignant mesothelioma is a rare malignancy with a poor prognosis whose development is related to asbestos fiber exposure. An increasing role of genetic predisposition has been recognized recently. Pleural biopsy is the gold standard for diagnosis, in which the identification of pleural invasion by atypical mesothelial cell is a major criterion. Pleural effusion is usually the first sign of disease; therefore, a cytological specimen is often the initial or the only specimen available for diagnosis. Given that reactive mesothelial cells may show marked atypia, the diagnosis of mesothelioma on cytomorphology alone is challenging. Accordingly, cell block preparation is encouraged, as it permits immunohistochemical staining. Traditional markers of mesothelioma such as glucose transporter 1 (GLUT1) and insulin‐like growth factor 2 mRNA‐binding protein 3 (IMP3) are informative, but difficult to interpret when reactive proliferations aberrantly stain positive. BRCA1‐associated protein 1 (BAP1) nuclear staining loss is highly specific for mesothelioma, but sensitivity is low in sarcomatoid tumors. Cyclin‐dependent kinase inhibitor 2A (CDKN2A)/p16 homozygous deletion, assessed by fluorescence in situ hybridization, is more specific for mesothelioma with better sensitivity, even in the sarcomatoid variant. The surrogate marker methylthioadenosine phosphorylase (MTAP) has been found to demonstrate excellent diagnostic correlation with p16. The purpose of this review is to provide an essential appraisal of the literature regarding the diagnostic value of many of these emerging biomarkers for malignant mesothelioma in effusion cytology.

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Genomic‐based ancillary assays offer improved diagnostic yield of effusion cytology with potential challenges in malignant pleural mesothelioma

Cited by 9 publications

References 49 publications

Short 57 kb CDKN2A FISH probe effectively detects short homozygous deletion of the 9p21 locus in malignant pleural mesothelioma

Short 57 kb CDKN2A FISH probe effectively detects short homozygous deletion of the 9p21 locus in malignant pleural mesothelioma

Fluorescence in situ hybridization detection of chromosome 22 monosomy in pleural effusion cytology for the diagnosis of mesothelioma

Diagnostic mesothelioma biomarkers in effusion cytology

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