Blood cancers are also referred to as hematologic cancers. They begin in tissuesTissueA group of cells that are alike; the material that organs, muscles, skin and other body parts are made up of such as the bone marrowBone MarrowSpongy tissue inside bones that contain stem cells (blood forming cells such as red cells, white cells or platelets) or in the cells of the immune systemImmune systemA system of the body that includes cells, tissues, and organs that helps the body fight infection or illness; the body’s natural defenses against germs and illness; the body’s ability to fight germs and illness. They can include lymphomas and leukemia, as well as other blood cancers.