Gains seen in fighting leukemia, but no cure

A term that literally means "white blood," leukemia describes a variety of cancers that originate in bone marrow, the soft material where blood cells are produced. People with leukemia have marrow that produces an overabundance of immature or diseased white blood cells at the expense of healthy white cells, red cells and platelets.

Types of leukemia are either grouped as chronic, meaning the condition worsens gradually, or acute, meaning it worsens quickly. Another way of grouping the cancers is by the type of white blood cell affected, either lymphoid cells or myeloid cells.

These groupings result in four common types of leukemia:

● Acute lymphocytic

(or lymphoblastic) leukemia

- ALL is the most common type of childhood cancer, affecting about 75 percent of children with leukemia.

● Acute myeloid

(or myelogenous) leukemia

-

A c

ancer of a group of seven types of white cells known as granuloyctes, AML affects affects about 15 percent of children with leukemia.

● Chronic lymphocytic leukemia

- CLL is largely diagnosed in people age 55 and older and almost never affects children.

● Chronic myeloid leukemia

- The type of leukemia diagnosed in Carlos Valencia, CML accounts for less than 5 percent of childhood leukemia cases. More than 90 percent of people diagnosed with CML have a genetic abnormality in the leukemia cells known as the "Philadelphia chromosome."