Acute leukemia is an aggressive disease characterized by accumulation of early bone marrow haemopoietic progenitors called blast cells.It is further subdivided into acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) on the basis of whether the blasts are shown morphologically to be myeloblasts or lymphoblasts respectively. Angiogenesis, or the formation of new blood vessels from pre-existing vessels during adult life, is an important natural process occurring in the body, both in health and in disease. Increase bone marrow angiogenesis has been demonstrated in a variety of solid tumors as well as hematologic disorders, including acute leukemia. Aim of the study: 1. Assessment of angiogenesis in acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) using anti-vWF and CD34 markers and count the number of microvessels by light microscope. 2. To investigate the correlation between the microvessel count & various clinicopathological parameters (age, sex, hepatomegaly, splenomegaly,
lymphadenopathy, Hb, WBCs count, platelets count, percentage of peripheral blood and bone marrow Blast) in patients with acute leukemia. Subjects, materials, and methods:This retrospective study was conducted from October 2006 to October 2007 on 38 samples of bone marrow biopsies including 19 cases of previously diagnosed acute lymphoblastic leukemia, 19 cases of acute myeloblastic leukemia and 14 age
matched reactive bone marrow considered as control cases, the cases were retrieved from archive files of Department of Pathology in the Teaching Laboratory of Medical City Hospital. From each, formalin fixed paraffin embedded bone marrow of AML and control subjects used in this study, 3 sections from each block were taken. One representative section was stained with Hematoxylin and Eosin (H&E) stain, while the other two sections were stained immunohistochemically for anti v.W.F. and CD34. Regarding ALL, only two sections from each block were stained; the first section with H&E and the second section was stained immunohistochemically for v.W.F alone.Clinicopathological parameters including age, sex, lymphadenopathy,
hepatomegaly, splenomegaly, hemoglobin level, white blood cells count, platelets count, blast cells percentage both in the peripheral blood and bone marrow were collected from the patients archive files.
All stained sections were examined by light microscopy at X100, X200, X400 magnification and three areas of the highest neovascularization (hot spots) were identified and the mean number of microvessls was calculated in these three hot spots and the results were expressed as mean vessel count per high power field (MVC/HPF), and used in statistical analysis.The bone marrow MVC estimations in patients with Acute Myeloblastic Leukemia and Acute Lymphoblastic Leukemia were compared with those of reactive bone marrow specimens Results: This study revealed that there was a significant increase in the microvessel
count in acute myeloid leukemia cases compared to control subjects with both antiCD34 (15.16±1.67 MVC/HPF) and anti-vWF (22.22±1.67 MVC/HPF), as well as in acute lymphoblastic leukemia using vWF (19.42±1.93 MVC/HPF) Moreover the MVC/HPF was significantly higher in AML than ALL (p=0.034) using antivWF. In addition there was no significant difference in the microvessel count between the different subtypes of AML neither by using CD34 nor with anti-vWF. There was no significant correlation between the mean vessel count in ALL, AML and the age, sex, hepatomegaly, splenomegaly, lymphadenopathy,
hemoglobin level, WBC count, platelet count, blast cell percentage both in the peripheral blood and bone marrow neither by using anti-vWF nor by anti CD34 Conclusion: This study showed that bone marrow angiogenesis was significantly increased in AML and ALL compared to control subjects. There was no significant difference in the microvessel count between the different subtypes of AML neither by using CD34 nor with anti-vWF.The MVC/HPF was significantly higher in AML than ALL using anti-vWF