Recurrent YAP1 and KMT2A gene rearrangements in a subset of MUC4-negative sclerosing epithelioid fibrosarcoma Journal Article


Authors: Kao, Y. C.; Lee, J. C.; Zhang, L.; Sung, Y. S.; Swanson, D.; Hsieh, T. H.; Liu, Y. R.; Agaram, N. P.; Huang, H. Y.; Dickson, B. C.; Antonescu, C. R.
Article Title: Recurrent YAP1 and KMT2A gene rearrangements in a subset of MUC4-negative sclerosing epithelioid fibrosarcoma
Abstract: Sclerosing epithelioid fibrosarcoma (SEF) is an aggressive soft tissue sarcoma, characterized by a distinctive epithelioid phenotype in a densely sclerotic collagenous stroma, that shows frequent MUC4 immunoreactivity and recurrent gene fusions, often involving EWSR1 gene. A pathogenetic link with low-grade fibromyxoid sarcoma (LGFMS) has been suggested, due to cases with hybrid morphology as well as overlapping genetic signature. However, a small subset of SEF is negative for MUC4 and lacks the canonical EWSR1/FUS gene rearrangements. Triggered by the identification of recurrent YAP1-KMT2A gene fusions by RNA sequencing in 3 index cases of MUC4-negative, EWSR1/FUS fusion-negative SEF, we further investigated a cohort of 14 similar SEF cases (MUC4-negative, EWSR1/FUS fusion-negative) by fluorescence in situ hybridization (FISH), reverse transcription-polymerase chain reaction, and/or DNA-based massively parallel sequencing (MSK-IMPACT) for abnormalities in these genes. Three additional SEFs with KMT2A gene rearrangements and one additional case with YAP1 gene rearrangements were identified by FISH. In addition, one case with YAP1-KMT2A and one with KMT2A-YAP1 fusion were detected by reverse transcription-polymerase chain reaction and MSK-IMPACT, respectively. As a control group, 24 fibromyxoid spindle cell tumors, diagnosed or suspected as fusion-negative LGFMS, were also tested for YAP1 and KMT2A abnormalities by FISH, but none were positive. The YAP1/KMT2A-rearranged SEF group affected patients ranging from 10 to 86 years old (average and median: 45) of both sexes (4 females, 5 males). The tumors involved somatic soft tissues with a wide distribution, including extremities, trunk, neck, and dura. Histologically, the tumors showed variable cellularity, with monotonous ovoid to epithelioid tumor cells and hyalinized collagenous background typical of SEF. More than half of the cases showed infiltrative borders, within fat or skeletal muscle. No LGFMS component was identified. All tumors were negative for MUC4 and had an otherwise nonspecific immunophenotype. Of the 6 cases with available follow-up information, 2 had local recurrences, and 2 developed soft tissue and/or bone metastases, including 1 of them died of the disease. © 2019 Wolters Kluwer Health, Inc. All rights reserved.
Keywords: yap1; mll; low-grade fibromyxoid sarcoma; sclerosing epithelioid fibrosarcoma; muc4; kmt2a
Journal Title: American Journal of Surgical Pathology
Volume: 44
Issue: 3
ISSN: 0147-5185
Publisher: Lippincott Williams & Wilkins  
Date Published: 2020-03-01
Start Page: 368
End Page: 377
Language: English
DOI: 10.1097/pas.0000000000001382
PUBMED: 31592798
PROVIDER: scopus
PMCID: PMC7012758
DOI/URL:
Notes: Article -- Export Date: 1 April 2020 -- Source: Scopus
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MSK Authors
  1. Narasimhan P Agaram
    190 Agaram
  2. Cristina R Antonescu
    895 Antonescu
  3. Lei Zhang
    194 Zhang
  4. Yun Shao Sung
    124 Sung