Leukemia is cancer of
the blood or bone marrow. Bone marrow produces blood cells, so individuals who
have leukemia have an abnormal production of blood cells. Usually the
abnormality is with the leukocytes, or white blood cells, and is the result of
damage to the DNA of immature cells. The cells grow and divide rapidly and do
not die, so they accumulate and eventually overtake the normal cells.
Leukemia is broken down into acute or chronic disease.
Acute leukemia progresses rapidly and results in an accumulation of the
useless, immature cells. Chronic disease progresses more slowly and allows for
mature useful cells to continue to be produced.
Lymphocytic leukemia occurs when the type of marrow that
makes lymphocytes is affected, and myelogenous leukemia occurs when the cancer
is in the type of marrow that produces red blood cells, other types of white
blood cells and platelets.
Types of leukemia include acute lymphocytic leukemia
(ALL), which most frequently occurs in children. Subtypes of ALL include
precursor B ALL, precursor T ALL, Burkitt’s leukemia and acute
biphenotypic leukemia. Chronic lymphocytic leukemia (CLL) occurs most
frequently in adults older than 55 years. Treatment of CLL is difficult and
some clinicians believe it is incurable. B-cell prolymphocytic leukemia is a
more aggressive type of CLL. Acute myelogenous leukemia (AML) more frequently
affects adults than children, and also more frequently affects men than women.
Types of AML include acute promyelocytic leukemia, acute myeloblastic leukemia
and acute megakaryoblastic leukemia. Chronic myelogenous leukemia (CML) affects
mostly adults.
Symptoms of leukemia include poor blood clotting, a poor
immune system, anemia, nausea, fever, chills, night sweats, flu-like symptoms,
headache and tiredness. Patients may experience an enlarged liver or spleen and
associated weight loss.
Leukemia may be caused by artificial ionizing radiation,
electromagnetic energy, human T-lymphocytic viruses or HIV, use of benzene or
other petrochemicals, hair dyes or alkylating chemotherapy agents used in
previous cancers. Genetic predisposition, Down syndrome and maternal fetal
transmission also have been linked as causes of leukemia.
Treatments for leukemia include chemotherapy drugs such
as imatinib mesylate, dasatinib and nilotinib. Patients may also undergo bone
marrow transplant.
Additional information can be found by searching the
following websites:
www.lls.org
www.cancer.gov/cancertopics/types/leukemia
www.ncbi.nlm.nih.gov/pubmed
http://health.nih.gov/topic/Leukemia