WT1 is a transcription factor essential to normal development of the human urogenital system. It is expressed in the fetal kidney and mesothelium, as well as in certain malignancies. It can be used to identify ovarian carcinoma and mesothelioma; levels of WT1 expression can also indicate disease progression in acute myeloid lymphoma. Furthermore, it is a potential target for cancer vaccines. In normal tissue, WT1 is positive in fallopian tube epithelium, smooth muscle cells and endothelial cells (nuclear and weak cytoplasmic localization), and testis. In cancer, it is positive in Wilms' tumor, malignant mesotheliomas, and serous ovarian adenocarcinomas. References: Proc Natl Acad Sci U S A. 2010 Aug 3;107(31):13824-9, PMID: 20631300; Cell. 1993 Aug 27;74(4):679-91, PMID: 8395349; Sexual Development. 2007;1(4):238-54, PMID: 18391535; Oncologist. 2012;17(2):250-9, PMID: 22291091; BMC Cancer. 2006 Apr 11;6:90, PMID: 16606472