CD99; T-cell surface glycoprotein E2; E2 antigen; protein MIC2; 12E7 (CD99, MIC2, MIC2X, MIC2Y)

Function

• role in T-cell adhesion processes
• involved in spontaneous rosette formation with erythrocytes

Structure

• extensively O-glycosylated
• belongs to the CD99 family

Compartment

• membrane; single-pass type 1 membrane protein (putative)

Alternative splicing

named isoforms=2

Expression

• ovarian granulosa cells
• pancreatic islet cells
• infant thymus
• Sertoli cells

Pathology

• associated with EWS-FLI1 fusion transcript, t(11;22)(q24;q12) causing FLI-1 protein overexpression
• tumors staining positive with antibody
  • T cell acute lymphoblastic lymphoma
  • calcifying aponeurotic fibroma
  • Ewing's sarcoma/PNET (95% sensitive, membranous staining, other tumors cytoplasmic)
  • gastrointestinal stromal tumor
  • intraabdominal desmoplastic small round cell tumor (23-35%)
  • leukemia cutis
  • nuchal fibromas
  • perineuroma (myxoid sclerosing type)
  • rhabdomyosarcoma (membranous staining)
  • sinonasal undifferentiated carcinoma (rare)
  • small cell carcinomas of lung (rare)
  • solitary fibrous tumor
  • synovial sarcoma
  • Wilm's tumors (some)
  • endometrial stromal tumors with sex cord differentiation
  • adult neuroblastoma stain negatively with antibody

Genetics

• the gene encoding for this protein is located in the pseudoautosomal region 1 (PAR1) of X & Y chromosomes

More general terms

• glycoprotein
• CD antigen

Database

• UniProt: http://www.uniprot.org/uniprot/P14209.html
• OMIM: https://mirror.omim.org/entry/313470
• OMIM: https://mirror.omim.org/entry/450000
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:4267
• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=4267