Pediatric Soft Tissue Tumors With BCOR ITD Express EGFR but Not OLIG2

Claudia M. Salgado, Angelica Zin, Marta Garrido, Irina Kletskaya, Rita DeVito, Miguel Reyes-Múgica, Gianni Bisogno, Vittoria Donofrio, Rita Alaggio

Research output: Contribution to journalArticlepeer-review

Abstract

Introduction: Somatic internal tandem duplication of 3’ of BCOR (BCOR ITD) has been found in clear cell sarcomas of the kidney (CCSK), soft tissue undifferentiated round cell sarcomas/primitive myxoid mesenchymal tumors of infancy (URCS/PMMTI), and a subgroup of central nervous system high-grade neuroepithelial tumors (CNS-HGNET). BCOR ITD+ tumors share morphologic features. Expression of OLIG2 and epidermal growth factor receptor (EGFR) has been reported in CNS-HGNET with BCOR ITD. Here, we characterize OLIG2 and EGFR expression in URCS/PMMTI with BCOR ITD. Methods: Paraffin blocks of 9 polymerase chain reaction-confirmed soft tissue BCOR ITD+ tumors (URCS/PMMTI) were immunophenotyped for OLIG2 and EGFR expression and scored semiquantitatively by percentage of positive cells and intensity of staining as negative, 1+, 2+, and 3+. Fluorescence in situ hybridization (FISH) for EGFR amplification was performed (amplification EGFR/CEP7 ratio ≥2.0). Results: All 9 tumors showed membrane/cytoplasmic expression of EGFR, strong and diffuse (3+) in 8 cases; weak (+2) in 1. FISH detected no EGFR amplification. OLIG2 was negative in all. Conclusions: EGFR is overexpressed in pediatric URCS/PMMTI with BCOR ITD and may be related to transcriptional upregulation of EGFR by BCOR ITD. OLIG2 negative staining differentiates URCS/PMMTI from CNS-HGNET. This finding may further support the possibility that these tumors have a different stem cell of origin.

Original languageEnglish
Pages (from-to)424-430
Number of pages7
JournalPediatric and Developmental Pathology
Volume23
Issue number6
DOIs
Publication statusPublished - Dec 2020

Keywords

  • BCOR
  • BCOR ITD
  • EGFR
  • OLIG2
  • PMMTI
  • URCS

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health
  • Pathology and Forensic Medicine

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