الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Acute lymphoblastic leukemia is a malignant neoplasm of the lymphocyte precursor cells - lymphoblasts- that occurs annually in nearly 4000 people in the USA. In Egypt, according to the National Cancer Registry (NCR), leukemia is the leading cause of malignancy in children, constituting 35.7% of cases of childhood cancer diagnosed annually. ALL is the main subtype of childhood leukemia (approximately 80%) and represents about 20% of acute leukemias in adults. It shows a bimodal age distribution with a peak incidence between two to five years and a smaller secondary peak after 60 years of age.
Conventional methods for diagnosis of ALL include peripheral blood and bone marrow examination, cytochemistry together with immunophenotyping by flowcytometry and conventional cytogenetics. Nowadays, molecular techniques are playing a major role in the diagnosis and identification of new abnormalities that may contribute to the susceptibility to ALL. These molecular techniques include fluorescence insitu hybridization and polymerase chain reaction.
Aberrant expression of myeloid antigens in B-ALL is a well recognized phenomenon. Sometimes it is associated with certain chromosomal translocations or has prognostic significance. It also can be of value for assessing minimal residual disease.
CD66c is a myeloid antigen. It is also a member of the carcinoembryonic antigen family. Within the hematopoietic system, CD66c expression is limited to granulocytes and their precursors. It is never expressed by normal and maturing B and T cells.
CD66c has been sporadically detected on AML cases particularly M2 and M4. It is also expressed in CML patients especially lymphoid blastic crisis of CML. CD66c is found in some non hematological malignancies e.g. colorectal tumors and pancreatic adenocarcinoma.
CD66c is aberrantly expressed in B-ALL patients. It is the most common myeloid antigen expressed in adult and pediatric B-ALL. CD66c is aberrantly expressed on B-ALL with strong correlation to genotype (negative in TEL/AML1 and MLL/AF4, positive in BCR/ABL and hyperdiploid cases). It also plays an important role in detection of MRD. But its prognostic significance is still under investigation.
The aim of this study was to evaluate the expression of the myeloid antigen CD66c in B-ALL patients, to determine whether CD66c is tightly associated with the BCR/ABL rearrangement. We also discussed the role of CD66c in the detection and the follow-up of minimal residual disease and its prognostic significance.
This study was carried out on a total of 60 subjects divided into two groups. The first group included 30 patients with precursor B lineage acute lymphoblastic leukemia (ALL) while the second group inclu