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Abstract
The biology of stem cells and their intrinsic properties are now recognized as integral to tumor pathogenesis in several types of cancer. This observation has broad ramifications in the cancer research field and is likely to impact our understanding of the basic mechanisms of tumor formation and the strategies we use to treat cancers. A role for stem cells has been demonstrated for cancers of the hematopoietic system, breast and brain. Going forward it is likely that stem cells will also be implicated in other malignancies. Hence, a detailed understanding of stem cells and how they mediate tumor pathogenesis will be critical in developing more effective cancer therapieies.
Acute lymphoblastic leukemia (ALL) represents the clonal proliferation of malignantly transformed lymphoid progenitors in the bone marrow and is the most common malignancy in the pediatric population. Close to 80% of ALL cases is a result of clonal expansion of B-cell precursors .It has been proposed that leukemias may be initiated by transforming event that take place in haematopoietic stem cells. Alternatively, leukemias may also arise from more committed progenitors caused by mutations and/or selective expression of genes that enhance their otherwise limited self-renewal capabilities.
This study aimed at defining the leukemia stem cells initiating cells expressing the surface markers CD 34, 38 and 19 in 20 newly diagnosed B-ALL cases before and after induction chemotherapy as apredictor for relapse if the patient still has these cells after induction chemotherapy. Also these markers may be useful for antibody-based or other related therapeutic regimens.
This study is concerned in the detection of the leukemic stem cells and leukemia initiating cells in 20 newly diagnosed patients of ALL from Cairo National Cancer Institute.
The patients were suitable to join this study since they are all diagnosed as pre B-ALL. All the patients examined were attendance of Cairo National Cancer Institute pediatric department during the period between December 2008 to May 2009.The recruited patients comprised 11 males and 9 females between the ages of 2 and 14 years.