Stains & molecular markers

Topic Completed: 1 April 2017

Minor changes: 24 December 2020

Copyright: 2003-2021,, Inc.

PubMed Search: WWTR1

Angela M.Y. Chan, M.Sc.
Page views in 2020: 95
Page views in 2021 to date: 7
Cite this page: Chan A, Enwere E. WWTR1. website. Accessed January 19th, 2021.
Definition / general
  • WWTR1, also known as TAZ (Transcriptional coactivator with PDZ binding motif), is a transcriptional coactivator that regulates expression of genes involved in cell proliferation and differentiation
  • The human WWTR1 gene codes for a protein with an apparent molecular weight of 50 - 55 kDa
Essential features
  • WWTR1 is negatively regulated by the Hippo signal transduction pathway
    • This pathway controls organ size by dynamically balancing the processes of cell proliferation and apoptosis (Nat Rev Cancer 2015;15:73)
  • WWTR1 functions interchangeably with its paralog, Yes associated protein (YAP)
  • In the absence of Hippo signaling, WWTR1 is predominantly present in the nucleus, where it interacts with various transcription factors to regulate gene expression
  • In the presence of Hippo signaling, it is retained in the cytoplasm and degraded
  • WWTR1 is overexpressed in many types of cancer (Cancer Cell 2016;29:783) and promotes metastasis through epithelial mesenchymal transition (Genes Dev 2012;26:54)
  • The human WWTR1 gene is on chromosome 3q24
  • WWTR1 (WW Domain Containing Transcription Regulator 1)
  • TAZ
  • Ubiquitously expressed predominantly in the nucleus but cytoplasmic expression is likely in cells with active Hippo pathways
Clinical features
Case reports
  • TAZ does not bind to DNA on its own but through interaction with TEAD transcription factors
  • Interruption of the TAZ-TEAD interaction can potentially be useful in the inhibition of the oncogenic role of TAZ
  • Currently no therapeutic is available to interrupt TAZ-TEAD interaction
  • Verteporfin is shown to block YAP-induced tumorigenesis (Genes Dev 2012;26:1300)
Microscopic (histologic) images

Images hosted on other servers:
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TAZ / YAP associated with increased grade

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Staining of WWTR1 in osteosarcoma

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YAP / TAZ widely
expressed and

Positive stains
  • Various types of cancer: brain, colon, kidney, liver, lung, pancreas
Negative stains
  • Skin, soft tissue
Board review style question #1
    Which assay(s) would support a diagnosis of epithelioid hemangioendothelioma with WWTR1-CAMTA1 fusion?

  1. CAMTA1 immunohistochemistry
  2. WWTR1-CAMTA1 break apart FISH
  3. WWTR1 immunohistochemistry
  4. (a) or (b)
  5. (b) or (c)
Board review style answer #1
D. While break apart FISH is sufficient for molecular confirmation, CAMTA1 mis-expression in epithelioid hemangioendotheliomas may also be indicative of this translocation event.
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