Wilms' tumor gene 1 (WT1) aberrations in testicular germ cell tumors (TGCTs).

4534 Background: Wilms’ tumor gene 1 (WT1) is a transcription factor essential for normal development of the urogenital system and male gonadal formation. Its alterations have been found in Wilms’ tumor, other malignancies and testicular dysgenesis syndromes. We studied WT1 aberrations to address its role in the pathogenesis of testicular germ cell tumors (TGCT). Methods: In fresh-frozen samples of 85 TGCT (48 seminomas, 37 non-seminomas), 3 stromal tumors and 88 non-neoplastic controls, expression of total WT1 and its four main isoforms was quantified by qPCR. WT1 mutations were detected by direct and next-generation sequencing (NGS). The presence of WT1 protein was evaluated by standard immunohistochemistry. Results: The total WT1 expression was significantly lower (1 log) in TGCT than in the controls and stromal tumors (Kruskal-Wallis p < 0.0001), and was lower in seminomas than non-seminomas. Testicular tissue surrounding TGCT and containing in situ lesions expressed similar WT1 levels like other cont...