CD25 (4C9), MMab

CD25 is the alpha chain of the IL-2 receptor. It is a Type I transmembrane protein present on activated T-cells, activated B-cells, some thymocytes, myeloid precursors, and oligodendrocytes that associates with CD122 to form a heterodimer that can act as a high-affinity receptor for IL-2. It is expressed in most B-cell neoplasms, some Acute Non-lymphocytic Leukemias, and Neuroblastomas.

CD25 antibody expression is a reliable diagnostic tool for distinguishing neoplastic mast-cell aggregates from reactive proliferations, and has, therefore, recently become a minor criterion for the diagnosis of Systemic Mastocytosis (SM). CD25 antibodies have also been useful in identifying mast cells in skin biopsies in the setting of Urticaria Pigmentosa, which is predictive of Systemic Mastocytosis. Quantitation of regulatory T-cells (Treg) in the setting of hepatocellular carcinoma has been used as an independent predictive factor for tumor recurrence after hepatic resection for HCC. Also, the percentage of tumor-infiltrating CD25+FOXP3+ regulatory T-cells among tumor cells, inside tumor parenchyma and at its periphery are significantly higher in recurrent Cutaneous Melanoma than in Non-recurrent Melanoma.