TLE1 is expressed in the majority of primary pleuropulmonary synovial sarcomas

Our plain-English summary of TLE1 is expressed in the majority of primary pleuropulmonary synovial sarcomas, by L.S. Lino-Silva, J.P. Flores-Gutiérrez, N. Vilches-Cisneros, et al (Virchows Archiv, 2011).

The study

• Authors: L.S. Lino-Silva, J.P. Flores-Gutiérrez, N. Vilches-Cisneros, H.R. Domínguez-Malagón
• Journal: Virchows Archiv
• Published: 2011;459(6):615-21
• Cited by: 21 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Pleuropulmonary synovial sarcoma (PPSS) is a rare entity, similar to synovial sarcoma of soft tissue (STSS). There are 120 published cases of PPSS, but no studies have explored the expression of TLE1. In soft tissues, it has been proven a useful marker, but in tumors of other sites, its expression has not been explored. The main objective was to study the expression and diagnostic sensitivity and specificity of TLE1 in a group of PPSS, of which the diagnosis was corroborated by fluorescence in situ hybridization confirming t(X;18) in a tissue microarray. Immunohistochemistry including TLE1, vimentin, CD99, CD56, bcl-2, AE1-AE3, EMA, CD34, CK7, CK19, calponin, and S-100 was performed on all PPSS and on 25 control cases (five carcinomas, ten mesotheliomas, and ten thoracic sarcomas). TLE1 was positive in 11 cases (73.3%); bcl-2 and vimentin in 100%; calponin and CD56 in 26.6%; CD99, CK AE1-AE3, CK19, CK7, and EMA in 80%; and S100 negative in all. The only biphasic PPSS was positive for epithelial markers only in the epithelial component. TLE1 was negative in all control cases. TLE1 is expressed in 73% of PPSS, a value inferior to that reported in STSS, but is highly specific for PPSS. TLE1 may therefore be of value in the differential diagnosis of PPSS, but should be used in a panel of antibodies.

© Springer-Verlag 2011

In plain English

This laboratory study examined pleuropulmonary synovial sarcoma, a rare lung and pleural tumor. It tested whether staining for a protein called TLE1 can distinguish this tumor from look-alike tumors, including mesothelioma. The authors searched their institution's pathology archives in Mexico for 2000 to 2010, finding 37 synovial sarcomas in the lung and pleura. They excluded 17 that had spread from elsewhere and five without enough tissue, leaving 15 cases. A genetic test (FISH) for the gene rearrangement typical of synovial sarcoma was positive in all 15. TLE1 staining was positive in 11 of the 15 tumors (73%). It was negative in all 25 comparison tumors: five spindle cell carcinomas, ten spindle cell mesotheliomas and ten other sarcomas. The authors reported this as 73% sensitivity and 100% specificity. The article's text reported five deaths from disease, but its case table lists seven. The authors concluded that TLE1 expression is highly specific but less frequent than reported in soft tissue synovial sarcoma. They noted that their mesothelioma comparison cases did not include epithelioid or mixed subtypes. The study did not examine asbestos exposure.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: retrospective case series from pathology archives, with immunohistochemistry and FISH testing and a comparison group of other tumors
• Who was studied: 15 primary pleuropulmonary synovial sarcomas from the authors' institution's archives, 2000 to 2010. Nine were in the lung and six in the pleura. Seven patients were male and eight female, with a median age of 37 years. Of 37 cases found, 17 metastatic cases and 5 cases lacking tissue were excluded. The study also used 25 comparison tumors: 5 spindle cell carcinomas, 10 spindle cell mesotheliomas, 6 malignant fibrous histiocytomas, 3 malignant peripheral nerve sheath tumors and 1 leiomyosarcoma.
• Main results:
  • The FISH test for the synovial sarcoma rearrangement was positive in all 15 cases (100%).
  • TLE1 staining was positive in 11 of the 15 pleuropulmonary synovial sarcomas (73%).
  • All 25 comparison tumors, including the 10 spindle cell mesotheliomas, were TLE1 negative. The authors reported 73% sensitivity and 100% specificity of TLE1 for pleuropulmonary synovial sarcoma.
  • Bcl-2 and vimentin staining were positive in 100% of the 15 cases.
  • Epithelial markers and CD99 were positive in two cases each (12%) on the tissue microarray, but in 12 cases (80%) on whole sections.
  • The results text reports that five of the 15 patients (33%) died of disease and ten were alive with progressive disease. Table 1 instead marks seven cases as dead of disease (cases 3, 4, 6, 8, 12, 13 and 14) and eight as alive with disease.
• The authors' conclusion: The authors concluded that TLE1 expression is highly specific for pleuropulmonary synovial sarcoma but less frequent than reported in soft tissue synovial sarcoma. They also concluded that FISH detection of the SYT rearrangement can be performed effectively on a tissue microarray.
• Limitations the authors state:
  • The mesothelioma comparison cases were all spindle cell mesotheliomas; epithelioid and mixed subtypes were not included.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Lung cancer.

Medical terms in this study, explained in our Lexicon: Synovial Sarcoma, Fluorescence In Situ Hybridization (FISH), Immunohistochemistry, CD34, S-100, Carcinoma, Mesothelioma, Sarcoma.

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