Bone marrow aspirate smear from a acute lymphocytic leukemia pdf with precursor B-cell ALL. The large purple cells are lymphoblasts.
ALL progresses rapidly and is typically fatal within weeks or months if left untreated. Most cases occur due to an unknown reason. This is then followed by further chemotherapy typically over a number of years. ALL affected about 876,000 people globally in 2015 and resulted in about 111,000 deaths. It occurs most commonly in children, particularly those between the ages of two and five.
In the United States it is the most common cause of cancer and death from cancer among children. The cancerous cell in ALL is the lymphoblast. Signals in the body control the number of lymphocytes so neither too few nor too many are made. In ALL, both the normal development of some lymphocytes and the control over the number of lymphoid cells become defective. In childhood ALL, this process begins at conception with the inheritance of some of these genes. These genes, in turn, increase the risk that more mutations will occur in developing lymphoid cells.