Gastroblastoma with a novel <scp><i>EWSR1‐CTBP1</i></scp> fusion presenting in adolescence
Selene C. Koo, Stephanie LaHaye, Bence Kővári, Kathleen M. Schieffer, Mark Ranalli, Jennifer H. Aldrink, Marc P. Michalsky, Susan I. Colace, Katherine E. Miller, Tracy A. Bedrosian, Kristen Leraas, Kyle Voytovich, Gregory Wheeler, Patrick J. Brennan, James Fitch, Benjamin Kelly, Sean McGrath, Anthony R. Miller, Peter White, Vincent Magrini, Richard K. Wilson, Elaine R. Mardis, Gregory Y. Lauwers, Peter B. Baker, Catherine E. Cottrell
Abstract
Gastroblastomas are rare tumors with a biphasic epithelioid/spindle cell morphology that typically present in early adulthood and have recurrent MALAT1-GLI1 fusions. We describe an adolescent patient with Wiskott-Aldrich syndrome who presented with a large submucosal gastric tumor with biphasic morphology. Despite histologic features consistent with gastroblastoma, a MALAT1-GLI1 fusion was not found in this patient's tumor; instead, comprehensive molecular profiling identified a novel EWSR1-CTBP1 fusion and no other significant genetic alterations. The tumor also overexpressed NOTCH and FGFR by RNA profiling. The novel fusion and expression profile suggest a role for epithelial-mesenchymal transition in this tumor, with potential implications for the pathogenesis of biphasic gastric tumors such as gastroblastoma.