Leukemia is cancer of the white blood cells, which play an important role in fighting infections.
All blood cells are produced in the bone marrow—the
spongy tissue in the center of bones. When a child has leukemia, too many
abnormal early-stage white blood cells are produced. This can interfere with
the production of red blood cells (which carry oxygen)
and platelets (which help blood clot). The abnormal
white blood cells can damage the function of many different organs and tissues
and can also invade the spinal fluid. Leukemia can occur in children of all
ages but affects boys more often than girls. Leukemia is believed to be caused
by genetic mutations—abnormal changes in the
genes of blood cells. Leukemia is not contagious and does not generally run
in families. The January 28, 2004, issue of JAMA includes
an article about clinical trials for children with leukemia.