CD99
MIM.313470 Xpter-p22.32
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The gene encoding CD99 surface antigen is located in the pseudoautosomal region (PAR) at the end of the short arm of the X and Y chromosomes. CD99 is a relatively non-specific marker for Ewing sarcoma and T-cell lymphoblastic lymphoma.
The monoclonal antibody 12E7 was raised against human leukemia T cells. It detects a 30,000 MW protein, now called CD99, which is expressed on all human tissues tested with the possible exception of spermatozoa.
Expression in normal cells
ovarian granulosa cells
pancreatic islets
infant thymus
Sertoli cells
Expression in tumors
Ewing sarcoma
lymphoblastic lymphoma (93%) (8163272)
large cell lymphoma (20%) (8163272)
small noncleaved cell lymphoma (5%) (8163272)
Positive staining (tumors): T cell acute lymphoblastic lymphoma, calcifying aponeurotic fibroma, Ewing?s sarcoma/PNET (95% sensitive), gastrointestinal stromal tumor, intraabdominal desmoplastic small round cell tumor (23-35%), leukemia cutis, nuchal fibromas, perineuroma (myxoid sclerosing type), rhabdomyosarcoma (membranous staining, AJSP 2002;26:1175), sinonasal undifferentiated carcinoma (rare, AJSP 2001;25:156), small cell carcinomas of lung (rare), solitary fibrous tumor, synovial sarcoma (poorly differentiated, monophasic and myxoid types), Wilm?s tumors (some), endometrial stromal tumors with sex cord differentiation
Negative staining: adult neuroblastoma