Leukemia is a type of blood cancer, mainly involves the white blood cells as you know, blood has different types of blood cells. Red blood cells, white blood cells, both originate from the marrow. In fact, marrow is the
factory of these cells. To begin with, there are stem cells or premature cells that have a potential to
become any type of blood vessel and the process of differentiation and getting mature to become
a functional white blood cell can be interrupted at any part of this maturation process. At that point, they become cancerous and they proliferate and they spill into the
blood and can cause problems because those are not really
functional white blood cells.