[The diagnostic value of CCNB3 and BCOR expression in BCOR-CCNB3 sarcoma]

Objective: To investigate the diagnostic value of expression of CCNB3 and BCOR in BCOR-CCNB3 sarcoma (BCS). Methods: Fifteen cases of BCS confirmed by fluorescence in situ hybridization (FISH) and/or reverse transcription-polymerase chain reaction (RT-PCR) from January 2014 to October 2021 at Beijing Jishuitan Hospital were collected. Immunohistochemical EnVision method was used to detect the expression of CCNB3 and BCOR in 15 cases of BCS and in 65 non-BCS tumors (54 cases of Ewing's sarcoma, 5 cases of CIC rearranged sarcoma, 4 cases of synovial sarcoma, 1 case of mesenchymal chondrosarcoma and 1 case of soft tissue clear cell sarcoma). Results: Immunohistochemical staining for CCNB3 revealed strongly diffuse nuclear staining in 14 of 15 (14/15) BCS cases, whereas none of the 65 non-BCS tumors showed any staining. Immunohistochemical staining for BCOR showed strongly diffuse nuclear staining in 11 (11/14) BCS cases; seven of the 65 (7/65, 10.8%) non-BCS tumors showed variable staining (five cases of Ewing sarcoma, one cases of synovial sarcoma, and one case of mesenchymal chondrosarcoma). The sensitivity and specificity of CCNB3 in diagnosing BCS were 93.3% and 100% and these of BCOR were 78.6% and 89.2%, respectively. Conclusions: CCNB3 is a highly sensitive and specific marker for BCS.The antibody may help screening BCS.