Comparison of immunohistochemistry, next-generation sequencing and fluorescence in situ hybridization for detection of MTAP loss in pleural mesothelioma Journal Article


Authors: Febres-Aldana, C. A.; Chang, J. C.; Jungbluth, A. A.; Adusumilli, P. S.; Bodd, F. M.; Frosina, D.; Geronimo, J. A.; Hernandez, E.; Irawan, H.; Offin, M. D.; Rekhtman, N.; Travis, W. D.; Vanderbilt, C.; Zauderer, M. G.; Zhang, Y.; Ladanyi, M.; Yang, S. R.; Sauter, J. L.
Article Title: Comparison of immunohistochemistry, next-generation sequencing and fluorescence in situ hybridization for detection of MTAP loss in pleural mesothelioma
Abstract: 9p21 deletions involving MTAP/CDKN2A genes are detected in diffuse pleural mesotheliomas (DPM) but are absent in benign mesothelial proliferations. Loss of MTAP expression by immunohistochemistry (IHC) is well accepted as a surrogate for 9p21 deletion to support a diagnosis of DPM. Accurate interpretation can be critical in the diagnosis of DPM, but variations in antibody performance may impact interpretation. The objectives of this study were to compare the performance of MTAP monoclonal antibodies (mAbs) EPR6893 and 1813 and to compare MTAP expression by IHC with 9p21 copy number status in DPM. Cytoplasmic expression of MTAP IHC with mAbs EPR6893 (ab126770; Abcam) and 1813 (NBP2-75730, Novus Biologicals) was evaluated in 56 DPM (47 epithelioid, 7 biphasic, and 2 sarcomatoid) profiled by targeted next-generation sequencing. 9p21 Copy number status was assessed by Fraction and Allele-Specific Copy Number Estimates from Tumor Sequencing (FACETS) analysis and also by CDKN2A fluorescence in situ hybridization in discrepant cases when material was available. MTAP mAb 1813 showed stronger immunoreactivity, more specific staining, and no equivocal interpretations compared to mAb EPR6893 which showed equivocal staining in 19 (34%) of cases due to weak or heterogenous immunoreactivity, lack of definitive internal positive control, and/or nonspecific background staining. MTAP expression with mAb 1813 showed near perfect agreement with 9p21 copy number by combined FACETS/fluorescence in situ hybridization calls (κ = 0.85; 95% CI, 0.71-0.99; P <.001). MTAP IHC with mAb 1813 was 96% sensitive, 86% specific, and 93% accurate for 9p21 homozygous deletion. The findings of this study suggest that interpretation of MTAP IHC is improved with mAb 1813 because mAb EPR6893 was often limited by equivocal interpretations. We show that MTAP IHC and molecular assays are complementary in detecting 9p21 homozygous deletion. MTAP IHC may be particularly useful for low tumor purity samples and in low-resource settings. © 2024 The Authors
Keywords: immunohistochemistry; adult; controlled study; human tissue; aged; human cell; major clinical study; somatic mutation; gene deletion; gold standard; clinical practice; allele; gene; cohort analysis; immunoreactivity; biopsy; histology; monoclonal antibody; tissue section; fluorescence in situ hybridization; tumor cell; pleura mesothelioma; mesothelioma; stroma; intermethod comparison; heterozygosity loss; cdkn2a; hybridization; chromosome 9; pleurodesis; mesothelium; high throughput sequencing; mtap; next-generation sequencing; very elderly; dna sequencing; human; male; female; article; diffuse pleural mesothelioma; 9p21 homozygous deletion
Journal Title: Modern Pathology
Volume: 37
Issue: 3
ISSN: 0893-3952
Publisher: Nature Research  
Date Published: 2024-03-01
Start Page: 100420
Language: English
DOI: 10.1016/j.modpat.2023.100420
PUBMED: 38185249
PROVIDER: scopus
PMCID: PMC11823465
DOI/URL:
Notes: The MSK Cancer Center Support Grant (P30 CA008748) is acknowledged in the PubMed record and PDF. Corresponding MSK author is Jennifer L. Sauter -- Source: Scopus
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MSK Authors
  1. Natasha Rekhtman
    425 Rekhtman
  2. Marc Ladanyi
    1328 Ladanyi
  3. William D Travis
    743 Travis
  4. Marjorie G Zauderer
    188 Zauderer
  5. Achim Jungbluth
    455 Jungbluth
  6. Denise Frosina
    123 Frosina
  7. Jason Chih-Peng Chang
    134 Chang
  8. Michael David Offin
    170 Offin
  9. Yanming Zhang
    199 Zhang
  10. Jennifer Lynn Sauter
    124 Sauter
  11. Francis M Bodd
    21 Bodd
  12. Soo Ryum Yang
    76 Yang
  13. Helen Irawan
    3 Irawan