CD 9

Biodesign (ALB6, MM2/57), Cymbus Bioscience (MM2/57), GenTrak, Immunotech (ALB6), Research Diagnostics (MM2/57), Sanbio (CLB/CD9), Seralab (FMC56, FMC8) and Serotec (MM 2/57).

Fresh-frozen tissue and cytologic preparations and formalin-fixed paraffin-embedded tissue.

The CD 9 antigen is a cell surface glycoprotein (p24) of molecular weight 24 kD belonging to the tetra-membrane-spanning protein family, coded by chromosome 12. The antigen is present on pre-B cells, monocytes and platelets and has protein kinase activity. The majority of mature peripheral blood or lymphoid tissue B cells or other normal circulating hematopoietic cells other than platelets do not express it. It is present on activated T-cells, mast cells and some dendritic reticulum cells (Kersey et al, 1981; Ash et al, 1982; Carbone et al, 1987).

The expression of CD 9 in malignant cells is complex and not strictly lineage, activation or differentiation associated. It is found in >75% of precursor B cell ALL/LBL, about 50% of B cell CLL and some better differentiated B-cell neoplasms such as prolymphocytic leukemia and multiple myeloma as well as some T-cell lymphomas, and acute myeloid leukemias. Other B cell lymphomas including centrocytic lymphoma, follicle center cell lymphoma and Burkitt's lymphoma, may also express this antigen and there is also variable expression on neuroblastomas and some epithelial tumors (Komada et al, 1983; San Miguel et al, 1986; Lardelli et al, 1990).

Because of its expression by a wide spectrum of B- and T-cell neoplasms and non-lymphoid tumors, this marker has limited application in the phenotypic analysis of hematopoietic neoplasms.

•Ash RC, Jansen J, Kersey JH et al 1982. Normal human pluripotential and committed hematopoietic progenitors do not express the p24 antigen detected by monoclonal antibody BA-2; implication for immunotherapy of lymphocytic leukemia. Blood 60: 1310-1316.

•Carbone A, Poletti A, Manconi R et al 1987. Heterogenous in situ immunotyping of follicular dendritic reticulum cells in malignant lymphomas of B cell origin. Cancer 60: 2919-2926.

•Kersey JH, LeBien TW, Abramson CS et al 1981. P24: a human leukemia associated and lymphohemopoietic progenitor cell surface structure identified with monoclonal antibody. Journal of Experimental Medicine 153: 726-731.

•Komada Y, Peiper SC, Melvin SL et al 1983. A monoclonal antibody (SJ-9A4) to p24 present on common ALLs, neuroblastoma and platelets. I. Characterization and development of a unique radioimmunometric assay. Leukemia Research 7: 487-498.

•Lardelli P, Bookman MA, Sundeen J et al 1990. Lymphocytic lymphoma of intermediate differentiation: morphologic and immunophenotypic spectrum and clinical correlations. American Journal of Surgical Pathology 14: 752-763.

•San Miguel JF, Caballero MD, Gonzalez M et al 1986. Immunological phenotype of neoplasms involving the B cell in the last step of differentiation. British Journal of Haematology 62: 75-83.

Manual of diagnostic antibodies for immunohistology / Anthony S.-Y. Leong, Kumarasen Cooper, F. Joel W.-M. Leong.