Acute Lymphoblastic Leukemia, ALL is one of the many types of blood cancer. It is also one of the least common types of blood cancer in adults. It originates from the white blood cells that are in the bone marrow and then moves to the other bone parts that are softer.

ALL is a type of leukemia that starts from white blood cells in the bone marrow, the soft inner part of bones. It develops from cells called lymphocytes, a type of white blood cell central to the immune system, or from lymphoblasts, an immature type of lymphocyte.