There are three major types of blood cancer: Leukemia,Lymphoma,Myeloma.These cancers cause your bone marrow and lymphatic system to make blood cells that don't work as well as they should. They all affect different types of white blood cells, and they act in different ways.All blood cancers are caused by faults in our DNA (mutations). Leukaemia is cancer of your white blood cells and bone marrow. Bone marrow is the place where blood cells are made in your body. With leukaemia, immature blood cells divide quickly and do not grow into mature cells. These immature cells crowd your bone marrow and prevent it from making normal healthy cells.Lymphoma is cancer of the lymphatic system. Generally, lymphoma cells grow in lymph glands (nodes). This causes the glands to get bigger or swell. Myeloma is a cancer of the plasma cells in the bone marrow, where red blood cells, white blood cells and platelets are made. Plasma cells, which are a kind of white blood cell, are also found in bone marrow. Normally, plasma cells make proteins called antibodies (immunoglobulins) to fight infection and help build up immunity to disease.