الفهرس 
INTRODUCTION
Neoangiogenesis and leukemiaOnly 14 pages are availabe for public view
 |  | from | 159 |  |  |
| | | from | 159 | | |
Abstract
Bone marrow (BM) is a hematopoietic organ that resides within the protected boundaries of the bones and is the major location for hematopoiesis. In adults, 4.6% of body weight is due to the BM that is distributed throughout the vertebrae, ribs, pelvis, skull and proximal ends of the long bones.
Hematopoietic stem cells (HSCs) have the ability to differentiate into all myeloid and lymphoid cell lineages and reproduce the entire hematopoietic and immune systems.
Acute leukemias are derived from primitive hematopoietic progenitor cells. Although they are rare cancers, accounting for less than 3% of all malignancies, they are the leading cause of death in persons younger than 35 years of age.
Chronic leukemia is characterized by the excessive build up of relatively mature, but still abnormal, white blood cells. Typically taking months or years to progress, the cells are produced at a much higher rate than normal, resulting in many abnormal white blood cells.
It has been well established that some hematopoietic diseases can dramatically affect the composition or function of certain cell types of the BM microenvironment, and that this in turn may further contribute to the severity of the hematopoietic disease.
BM microenvironment may induce leukemia. Recent data indicate that, in parallel with leukemogenic events in the hematopoietic system, the niche is converted into an environment with dominant signals that favor cell proliferation and growth. The microenvironment may have a role in determining the lineage commitment of leukemia.
By elucidating the role of the BM microenvironment in the pathogenesis of hematologic tumors, recent studies have provided the framework for identifying and validating novel therapies that target both leukemic cells and cells in their surrounding microenvironment.