Aberrant Expression of CD56 in Patients With Hematologic Malignancies.

CD56 is the archetypal phenotypic marker of natural killer cells but can actually be expressed by many more immune cells, including alpha, beta T cells, gamma, delta T cells, dendritic cells, and monocytes. Common to all these CD56 expressing cell types have strong immunostimulatory effector functions, including T helper 1 cytokine production and an efficient cytotoxic capacity. Interestingly, both numerical , functional deficiencies and phenotypic alterations of the CD56 immune cell fraction have been reported in patients with various infectious, autoimmune, or malignant diseases.CD56 is also known as neural cell adhesion molecule (NCAM).

Hematologic malignancies are a heterogeneous group of diseases of diverse incidence, prognosis and etiology that arise from malignant transformation of cells from the bone marrow or the lymphatic system.There are two major groups of Hematologic malignancies according to their cell lineage: Myeloid and lymphoid. Lymphoid neoplasms are a varied group that includes non-Hodgkin lymphoma (NHL), Hodgkin lymphoma (HL), leukemia and multiple myeloma (MM).myeloid neoplasms and acute leukaemia include: Myeloproliferative neoplasms (MPN), Myelodysplastic/myeloproliferative neoplasms (MDS/MPN), Myelodysplastic syndromes (MDS), Acute myeloid leukaemia (AML), Acute leukemias of ambiguous lineage, B-lymphoblastic leukaemia/lymphoma, T-lymphoblastic leukaemia/lymphoma.The exact causes of Hematologic malignancies are still unknown although multiple epidemiological studies have reported an association between the development of Hematologic malignancies and several risk factors. Some factors are well documented to increase the risk of some types of leukaemia such as benzene exposure and ionizing radiation.However, many other factors were observed to have an association with Hematologic malignancies such as age, gender, tobacco smoking , obesity , hepatitis C virus (HCV) infection , family history , and environmental exposure to pesticides but with no clear evidence.

CD56 was found to be ectopically expressed in multiple myeloma. A met analysis indicated that CD56 over expression may be an adverse prognostic factor in AML. To the best of our knowledge, no available data the expression pattern of CD56 in other Hematologic malignancies. This work is designed to evaluate the expression pattern of CD56 in hematologic malignancies.