Stains & CD markers
Transducin-like enhancer of split 1 (TLE1)

Last author update: 28 April 2022
Last staff update: 11 October 2022

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PubMed Search: Transducin-like enhancer of split 1 (TLE1)

Anna Dusenbery, M.D.
Mark R. Wick, M.D.
Page views in 2022: 9,743
Page views in 2023 to date: 11,236
Cite this page: Dusenbery A, Wick MR. Transducin-like enhancer of split 1 (TLE1). website. Accessed November 29th, 2023.
Definition / general
Essential features
  • TLE1 immunohistochemical staining is most commonly used when synovial sarcoma is a diagnostic consideration; in this setting, nuclear expression should be observed
    • Sensitivity and specificity are reasonable for this purpose; however, an increasing number of entities have demonstrated TLE1 expression with varying frequency
  • Should be interpreted in the appropriate context of histomorphologic, molecular and other immunohistochemical features (Ann Diagn Pathol 2014;18:369)
  • The protein product of this gene, TLE1, is a transcriptional corepressor, homologous to the corepressor groucho in Drosophila
  • Functions as either an oncogene or tumor suppressor in various cancer types (Oncotarget 2017;8:15971)
  • Repression by TLE1 involves histone deacetylase (HDAC) activity
Uses by pathologists
  • Reasonably sensitive and specific for synovial sarcoma within the appropriate context; this includes its monophasic, biphasic and poorly differentiated forms
  • Laboratory considerations:
    • One study demonstrated a better overall immunohistochemistry performance profile with a monoclonal TLE1 antibody, as opposed to a polyclonal TLE1 antibody (Appl Immunohistochem Mol Morphol 2019;27:174)
    • Another study demonstrated fairly similar performance of both a monoclonal pan-TLE antibody and a polyclonal TLE1 antibody; there were only 8 discrepancies in scoring among 177 cases, all of which demonstrated staining with the monoclonal pan-TLE antibody but not with the polyclonal TLE1 antibody (Am J Surg Pathol 2007;31:240)
Prognostic factors
Microscopic (histologic) images

Contributed by Mark R. Wick, M.D.
Monophasic synovial sarcoma, H&E

Monophasic synovial sarcoma

Monophasic synovial sarcoma, TLE1

TLE1 in monophasic synovial sarcoma

Biphasic synovial sarcoma, H&E

Biphasic synovial sarcoma

Biphasic synovial sarcoma, TLE1

TLE1 in biphasic synovial sarcoma

Contributed by Debra L. Zynger, M.D.
Monophasic synovial sarcoma, H&E

Monophasic synovial sarcoma

Monophasic synovial sarcoma, TLE1 positive

TLE1 positivity in monophasic synovial sarcoma

Malignant peripheral nerve sheath tumor, H&E

Malignant peripheral nerve sheath tumor

Malignant peripheral nerve sheath tumor, TLE1 negative

TLE1 negativity in malignant peripheral nerve sheath tumor

Positive staining - normal
Positive staining - disease
Negative staining
Molecular / cytogenetics description
  • Synovial sarcoma is classically characterized by t(X;18), which leads to SS18-SSX gene fusions, for which fluorescence in situ hybridization (FISH) has been shown to have a sensitivity of 86 - 97% and a specificity of up to 100%
  • TLE1 immunostains can be useful in identifying a specific subpopulation of tumor cells for FISH analysis or in cases with cryptic X;18 rearrangement (Am J Surg Pathol 2009;33:1743)
Sample pathology report
  • Soft tissue, right anterior thigh, biopsy:
    • Synovial sarcoma, monophasic type (see comment)
    • Comment: Microscopic examination demonstrates a monotonous spindle cell proliferation with a fascicular to storiform architecture. Up to 8 mitoses per 10 high power fields are noted. Immunohistochemical stains demonstrate that the tumor cells strongly and diffusely express BCL2 (cytoplasmic) and TLE1 (nuclear). There is very focal EMA expression. The tumor cells are negative for S100, myogenin, myoD1, CD34, MUC4 and ERG. Fluorescence in situ hybridization for SS18 demonstrates a gene rearrangement (see addendum report for full details). These findings support the diagnosis of synovial sarcoma.
Board review style question #1
Which of the following pathways is inhibited by TLE1?

  1. IGF signaling pathway
  2. JAK / STAT signaling pathway
  3. MAPK signaling pathway
  4. VEGF signaling pathway
  5. WNT / beta catenin signaling pathway
Board review style answer #1
E. WNT / beta catenin signaling pathway

Comment Here

Reference: Transducin-like enhancer of split 1 (TLE1)
Board review style question #2

H&E and TLE1 IHC of a spindle cell neoplasm are pictured in the images above. Which of the following translocations would additionally support the suspected diagnosis of synovial sarcoma?

  1. t(2;5)
  2. t(11;22)
  3. t(14;18)
  4. t(17;22)
  5. t(X;18)
Board review style answer #2
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