New Sarcoma Defined by BCORCCNB 3 Fusion Laila

New Sarcoma Defined by BCORCCNB 3 Fusion Laila Moharram, Hussam Haddad King Hussein Cancer Center

Case History • 13 year old male • Left pelvic mass

Pediatric Round cell Sarcomas • • • Rhabomyosarcoma Ewing sarcoma/PNET Neuroblastoma Lymphoma/ leukemia Small cell osteosarcoma Mesenchymal chondrosarcoma • Sclerosing RMS • BRD/NUT carcinoma • Extrarenal rhabdoid tumor • Desmoplastic small round cell tumor • Undifferentiated sarcoma

CD 99 PAS

Myogenin Desmin

BAF 47 BCL-2

Immunostains Positive CD 99 (Weak) BCL-2 CD 56 Negative synaptophysin desmin, myogenin S 100 protein CD 31 EMA and CK-MNF FLI-1

EWSR 1 Fusion Partners • • • FLI 1 (85%) ERG (5 -10%) FEV ETV 1 E 1 Af EWSR 1 -ETS

Working Diagnosis Small round blue cell tumor of the bone • FISH is negative for EWSR 1 rearrangement

EWSR 1 fusion negative Ewing sarcoma • Rare • FUS FISH • FUS-ERG or FUS-FEV

Diagnosis? DX: Undifferentiated spindle and round cell sarcoma.

Undifferentiated sarcoma • Fusion negative Ewing-like neoplasms • CD 99: Positive, focal or negative. • Proportion of cases shows new fusion CIC-DUX 4 • t(4; 19) • t(10; 19)

Consultation CIC-DUX 4 gene fusion negative The tumor instead showed BCOR-CCNB 3 fusion.

• Fusion-specific RT-PCR to screen a series of 594 sarcomas. • 24 BCOR-CCNB 3–positive tumors were identified

• Gene profiling experiments indicated that BCOR-CCNB 3–positive cases are biologically distinct from other sarcomas, particularly Ewing sarcoma.

BCOR-CCNB 3 Sarcoma • • Clinical description is similar to Ewing Sarcoma. Median age 13 years Male predominance Preferentially long bones, the spine and pelvis. • 20%: soft tissue tumor.

Pathology • Undifferentiated, small round cell sarcoma, suggestive of the Ewing sarcoma. • Half lacked strong membrane positivity for CD 99.

BCOR and CCNB 3 Genes • Both on the X chromosome • BCOR encodes ubiquitous transcriptional repressor that associates with BCL 6 oncoprotein • CCNB 3 expression is tightly restricted to the testis, with CCNB 3 encoding an early meiotic cyclin.

• Ectopic expression of CCNB 3 as a result of the BCOR gene fusion may constitute a key oncogenic event.

Undifferentiated/ unclassifed Sarcomas • Introduced a chapter on undifferentiated sarcomas. • No reproducible immunophenotype. • Patchy CD 99 • CD 34+-: No discriminatory value. • EM: No evidence of differentiation.

Ewing or Ewing look-alike? Undifferentiated Sarcoma CIC-DUX 4 sarcoma? BCOR-CCNB 3 sarcoma

References 1. Italiano A, Sung YS, Zhang L, Singer S, Maki RG, Coindre J-M, Antonescu CR. High prevalence of CIC fusion with double-homeobox (DUX 4) transcription factors in EWSR 1 - negative undifferentiated small blue round cell sarcomas. Genes Chromosomes Cancer 2012; 51: 207 -218. 2. Pierron G et al. A new subtype of bone sarcoma defined by BCOR-CCNB 3 gene fusion. Nat Gen 2012; 44: 461 -466. 3. Barr FG, Womer RB. Molecular diagnosis of Ewing family tumors too many fusions. . . ? Journal of Molecular Diagnostics. 2007; 9(4): 437– 440. 4. Shing DC, Mc. Mullan DJ, Roberts P et al. FUS/ERG gene fusions in Ewing’s tumors. Cancer Res 2003; 63: 4568– 4576. 5. French CA, Kutok JL, Faquin WC, Toretsky JA, Antonescu CR, Griffin CA, et al. Midline carcinoma of children and young adults with NUT rearrangement. J Clin Oncol. 2004; 22(20): 4135– 4139.

References 6. Ng TL, O’Sullivan MJ, Pallen CJ, Hayes M, Clarkson PW, Winstanley M, Sorensen PH, Nielsen TO, Horsman DE. Ewing sarcoma with novel translocation t(2; 16) producing an in-frame fusion of FUS and FEV. J Mol Diagn. 2007; 9: 459– 463. 7. Kawamura-Saito M, Yamazaki Y, Kaneko K, Kawaguchi N, Kanda H, Mukai H, Gotoh T, Motoi T, Fukayama M, Aburatani H, Takizawa T, Nakamura T. Fusion between CIC and DUX 4 up- regulates PEA 3 family genes in Ewing-like sarcomas with t (4; 19)(q 35; q 13) translocation. Hum Mol Genet 2006; 15: 2125 - 2137 8. Bridge RS, Rajaram V, Dehner LP, Pfeifer JD, Perry A. Molecular diagnosis of Ewing sarcoma/primitive neuroectodermal tumor in routinely processed tissue: a comparison of two FISH strategies and RT-PCR in malignant round cell tumors. Modern Pathology. 2006; 19(1): 1– 8.