Acute myeloid leukemia, or AML, is a type of blood cancer. It is a quickly progressing disease in which too many abnormal white blood cells are found in the bone marrow, the soft, spongy center of long bones. In AML, myeloid stem cells (a type of blood stem cell) become immature white blood cells called myeloblasts or “blasts.” These blasts do not become healthy white blood cells. Instead, they build up in the bone marrow, so there is less room for healthy white blood cells, red blood cells and platelets. In addition, these abnormal cells are unable to fight off infection.