Leukemia and aplastic anemia are both diseases that originate within the bone marrow, states MedlinePlus. Other cancers, such as lymphoma, may also spread into the bone marrow as they progress.
Bone marrow is a tissue that is found within some of the major bones of the human body, states MedlinePlus. This spongy tissue contains stem cells that have the ability to proliferate and mature into healthy red blood cells, white blood cells and platelets. If bone marrow becomes diseased due to cancer or anemia, then stem cells may be affected and blood cell and platelet counts may increase or decrease.