Chronic Lymphocytic Leukemia - The Leukemia & Lymphoma Society

Enlargement of the spleen is called “splenomegaly.” Surgical removal of the spleen
is known as “splenectomy.” Certain diseases are treated by removing the spleen.
Most of the functions of the spleen can be performed by other organs, such as the
lymph nodes and liver, but a person whose spleen has been removed is at higher
risk for infection. He or she is given antibiotic therapy immediately at the first sign
of infection, such as a fever.
Stem Cells. Primitive cells in the marrow that are essential to the formation of red
cells, white cells and platelets. Stem cells are largely found in the marrow, but some
leave the marrow and circulate in the blood. Using special techniques, the stem cells
in the blood can be collected, preserved by freezing and later thawed and used for
stem cell therapy. See Hematopoiesis.
Stem Cell Transplantation. See Allogeneic Stem Cell Transplantation;
Autologous Stem Cell Transplantation.
Thrombocytopenia. A decrease to a below-normal concentration of platelets in
the blood.
Translocation. An abnormality of chromosomes in the marrow or lymph node
cells that occurs when a piece of one chromosome breaks off and attaches to
the end of another chromosome. In a balanced translocation, genetic material is
exchanged between two different chromosomes with no gain or loss of genetic
information. When a translocation occurs, the gene at which the break occurs is
altered. This is one form of somatic mutation that may transform the gene into an
oncogene (cancer-causing gene). See Mutation.
White Cells. Any of the five major types of infection-fighting white cells in the
blood: neutrophils, eosinophils, basophils, monocytes and lymphocytes. White cells
are also called “leukocytes.”
ZAP-70. An abbreviation for the cell protein “zeta-associated protein 70.” A high
level of ZAP-70 expression on the cells of patients with B-cell CLL is one of several
factors that may predict more progressive disease. Outside of a research laboratory
this test is generally not very reliable and should not be used.
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