Role of Endoglin Expression in Acute Myeloblastic Leukemia

Abstract
Background: Endoglin (CD105), a cell membrane glyco-protein of approximately 180kDa, has been described as a proliferation-associated antigen of leukemia and endothelial cells, and it represents a powerful marker to quantify tumor angiogenesis. CD105 expression is higher on leukemic cells with immature morphological and phenotypic characteristics compared to normal hematopoietic progenitors. Higher amounts of sCD105 were measured in AML and Chronic Myeloproliferative Disorders (CMD) patients than in healthy subjects. CD105 is involved in the control of vascular en-dothelial cell proliferation, adhesion and migration. CD105 might have a direct involvement in cancer by increase of tumor mass. CD105 levels may be useful as an indicator for disease progression and to identify patients at risk of recurrence and metastasis.
Aim of Study: Our aim is to evaluate the role of endoglin (CD 105) expression in patients with AML to clarify its role as a prognostic marker.
Material and Methods: This study was carried out on 50 patients with newly diagnosed acute myeloid leukemia who attended the Hematology/Oncology Unit of Tanta University Hospitals. The patients were selected for the study on the basis of standard clinical, hematological and immune pheno-typic criteria for diagnosis of AML. CD105 expression was measured in bone marrow aspirate of AML patients using RD SYSTEMS kits and BD FACS calibur.
Subjects included in this study were divided into two groups according to CD 105 exppression; positive and negative groups and classified according to FAB subtypes and immu-nophenotypic features.
Results: There was a significant difference in distribution of CD105 expression in different FAB subtypes. There was a significant positive correlation between CD 105 expression and Hb concentration, WBCs count and blast count in periph-eral blood and BM. There was no significant correlation between CD105 expression and platelets count and serum LDH level. Kaplan-Meier survival curve show significant higher overall survival and disease free survival in negative CD105 expression group than in positive CD105 expression group.
Conclusions: Positive CD105 expression levels are asso-ciated with a bad outcome in AML patients and its expression can be easy determined in routine flow cytometric analysis. Therefore, it should be regularly investigated as a bad prog-nostic factor for assessment of AML patients.