Blood

With the exception of acute lymphoblastic leukemia, which has its peak incidence in childhood, cancer of the blood is a disease of older adults. While the "cause" of cancer is not entirely understood, great advances in our understanding of the nature of this disease were made in the last two decades of the twentieth century. It is now apparent that in most, and likely in all, cancers, genetic mutations lead to alterations in the normal cellular programs of differentiation, proliferation, and programmed cell death (apoptosis). Many of these discoveries have come from research on the cancers of the blood.