Test Details: Immunohistochemical testing is carried out on biopsy/resected tissue specimen. This testing helps to identify specific antigens (proteins) within tissue sections utilizing an antigen-specific antibody .Wilms tumour protein-1 (WT-1) is a transcriptional regulator encoded by the WT-1 gene on chromosome 11p13 with four isoforms. WT-1 plays an important role in the regulation of growth factors and development of tissues from the inner layer of intermediate mesoderm including the genitourinary system, mesothelial cells and spleen. WT-1 shows two different expression patterns: first, a true nuclear expression pattern characteristic for different tumours such as serous carcinomas of ovarian, tubal and peritoneal origin and mesothelioma; secondly a cytoplasmic staining pattern found in endothelium and vascular tumours in addition to some carcinoma types such as pulmonary adenocarcinoma. It is a diagnostic marker of Nephroblastoma.