Pediatric Soft Tissue Tumors With BCOR ITD Express EGFR but Not OLIG2. (December 2020)

• Record Type: Journal Article
• Authors: Salgado, Claudia M.; Zin, Angelica; Garrido, Marta; Kletskaya, Irina; DeVito, Rita; Reyes-Múgica, Miguel; Bisogno, Gianni; Donofrio, Vittoria; Alaggio, Rita
• Is Part Of: Pediatric and developmental pathology. Volume 23:Number 6(2020)
• Page Start: 424
• Page End: 430
• Publication Date: 2020-12
• Subjects: BCOR ITD -- EGFR -- OLIG2 -- PMMTI -- URCS -- BCOR; Pediatric pathology -- Periodicals; Children -- Diseases -- Periodicals; Diagnosis, Laboratory -- Periodicals; Abnormalities, Human -- Periodicals; Child development -- Periodicals; Pediatrics -- Periodicals; 616.07
• DOI: 10.1177/1093526620945528
• Languages: English
• ISSNs: 1093-5266

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.