Wilms Tumor Protein 1 (WT1)

The Wilms Tumor Protein 1 (WT1) test is an immunohistochemistry (IHC) examination used to detect the expression of the WT1 protein, a transcription factor encoded by the WT1 gene on chromosome 11p13. WT1 plays an important role in the normal development of the kidneys and gonads and is expressed in several tumour types, making it a valuable diagnostic and prognostic marker in oncology.

Initially identified in Wilms tumour (nephroblastoma), WT1 is now widely used in the diagnosis and classification of various malignancies, including mesothelioma, ovarian serous carcinoma, leukaemia, desmoplastic small round cell tumour, sex cord stromal tumours, and certain sarcomas. The pattern of WT1 expression-  particularly nuclear staining, helps pathologists differentiate between tumour types, determine tumour origin, and support treatment planning.

Who Should Get This Test Done?

This test may be recommended if individuals:

●     Have suspected or confirmed mesothelioma, ovarian serous carcinoma, or peritoneal tumours that require accurate tumour classification and differentiation from other cancers.

●     Have pleural, peritoneal, undifferentiated, or poorly differentiated tumours where the tissue of origin is uncertain and further immunohistochemical evaluation is needed.

●     Have acute myeloid leukaemia (AML) or acute lymphoblastic leukaemia (ALL) and require WT1 assessment for diagnosis, prognosis, or disease monitoring.

●     Have a childhood kidney tumour suspected to be Wilms tumour, or a small round cell tumour where desmoplastic small round cell tumour is being considered.

●     Have sex cord stromal tumours of the ovary or testis, or require monitoring of leukaemia treatment response using WT1 as a minimal residual disease marker.

Why Consider This Test?

WT1 is an important diagnostic marker in several challenging cancer types. In mesothelioma, WT1 nuclear positivity is one of the most useful markers for distinguishing the tumour from metastatic adenocarcinomas, a distinction that significantly affects treatment and prognosis.

In ovarian and primary peritoneal serous carcinomas, WT1 expression helps identify tumour lineage and differentiate these cancers from metastatic tumours of non-gynaecological origin. In AML, WT1 serves as a sensitive marker for monitoring minimal residual disease, helping detect treatment response, relapse, or disease progression at an early stage.

For childhood kidney tumours and other rare malignancies, WT1 contributes valuable information that supports accurate diagnosis, treatment planning, and prognostic assessment.

More Information

The Wilms Tumor Protein 1 (WT1) test evaluates the expression of the WT1 gene or protein, which plays an important role in normal cell growth and development. Changes in WT1 expression are associated with certain blood cancers and other tumors, making the test useful in their evaluation. It is commonly performed as part of a comprehensive diagnostic work-up and, in some cases, may also help monitor disease status over time. The results are always interpreted along with clinical findings and other laboratory or molecular tests to provide a complete assessment.

Other Names

●     WT1 Immunohistochemistry

●     Wilms Tumour Antigen IHC

●     WT1 Protein Expression Test

●     WT1 IHC – Tissue

●     Nephroblastoma Marker – WT1

●     Anti-WT1 Antibody Test – Tissue

●     WT1 Nuclear Staining Test

●     WT1 Expression Analysis – Paraffin Block

●     Wilms Tumour Gene Product IHC