Evaluation of the incidence and clinical significance of WT-1 expression in uterine serous carcinoma()

BACKGROUND: Wilms tumor gene 1 (WT1) expression is a hallmark of ovarian serous carcinoma and considered to be diagnostic marker of these tumors, differentiating them from uterine serous carcinoma (USC), historically thought to rarely express WT1. However, more recent data indicates a significant percentage of USC may express WT1. The clinical implications of WT1 positivity in USC remain unclear. METHODS: A multicenter retrospective analysis of patients with USC was conducted from 2000 to 2019. Inclusion criteria were patients who had undergone comprehensive surgical staging/tumor debulking with archival tissue available for WT1 assessment via immunohistochemistry (IHC). Chemosensitive patients were defined as those recurring >6 months from last platinum-based chemotherapy. Progression free survival (PFS) and overall survival (OS) analysis was performed using Kaplan-Meier estimates. Multivariate analysis (MVA) was performed using Cox proportional hazards model. RESULTS: WT1 status was evaluated in 61 patients with USC. 13 (21.3%) were positive for WT1 by IHC. Stage distribution included 32% stage I, 5% stage II, 25% stage III and 38% stage IV. There was no difference in the stage (p = 0.158), race (p = 0.227) or distribution of recurrence sites (p = 0.581) between WT1 positive and WT1 negative tumors. The majority of patients were chemosensitive (63%). Chemosensitivity was significantly improved in WT1 positive (92.3%) vs. WT1 negative tumors (55.8%) (p = 0.016). We observed a trend towards improved PFS among WT1 positive tumors (21 vs. 16-months, respectively) (p = 0.544). On MVA, stage (p < 0.001) and chemosensitivity (p < 0.001) were independent predictors of PFS. CONCLUSIONS: WT1 positivity is observed in over 20% of USC. WT1 expression is associated with improved chemosensitivity which may contribute to improvements in PFS.