Brachyury, a driver of epithelial mesenchymal transition, as an independent prognostic factor in high-grade testicular germ cell tumors.

Abstract

e16039 Background: The T-box transcription factor Brachyury has been considered a cancer-specific marker and a novel oncotarget in solid tumors. Brachyury overexpression has been described in various cancers, being associated with epithelial-mesenchymal transition, metastasis and poor prognosis. However, its clinical association with testicular germ cell tumor (TGCT) is unknown. Methods: We analyzed the expression of Brachyury both at protein and transcript levels in a series of 96 TGCT samples and by in silico analysis, respectively. Additionally, we investigated the clinical significance of Brachyury in TGCT. Results: Brachyury protein showed to be over-represented in 89.6% (86/96) of TGCT cases with nuclear staining in 24% (23/96) of them. Microarray expression analysis in two independent cohorts of TGCTs showed similar results with increased levels of Brachyury in TGCTs and metastasis compared with normal testis. Clinically, Brachyury nuclear staining was statistically associated with event-free survival (p = 0.04) and overall survival (p = 0.01) in intermediate/high-risk TGCTs. Multivariate analysis showed that Brachyury nuclear subcellular localization was an independent predictor of poor prognosis (HR: 3.56, p = 0.06). Conclusions: These results indicate that Brachyury plays an oncogenic role in TGCTs and its subcellular localization in the nucleus is a potential novel biomarker of poor prognosis and an oncotarget for intermediate/high-risk TGCTs treatment.