Leukemia Types All Lymphoblastic

Some 5,760 new cases of acute lymphocytic leukemia (ALL) are diagnosed in the United States every year, according to the American Cancer Society (2009). Of this number, more than 3,000 are cases of childhood acute lymphocytic leukemia. The Children’s Hospital in Boston, Massachusetts reports that ALL accounts for 75 percent of childhood leukemia cases, making it the most common type of childhood cancer. Peak incidence rates are between the ages of 2 and 5, although the disease can develop at any age.

Acute Lymphocytic Leukemia Progression

Acute lymphocytic leukemia, also known as acute lymphoblastic leukemia, is characterized by the accumulation of immature lymphocytes, or blasts, in the blood stream and bone marrow. In early stages, healthy lymphocytes develop into mature white blood cells, but abnormal lymphocytes don’t develop properly. Rapid reproduction of abnormal lymphocytes causes high white blood cell counts and low levels of red blood cells.

Types of Leukemia

Acute lymphocytic leukemia is only one of several types of leukemia: Chronic lymphocytic leukemia also involves abnormal lymphocytes. Non-lymphocytic leukemia develops in a different type of blood cell, called myeloid cells. There are two types of leukemia in this category: acute non-lymphocytic leukemia and chronic myelogenous leukemia.

Diagnosing Acute Lymphocytic Leukemia

Excessively high white blood cell counts may indicate the presence of ALL. Blood tests and bone marrow biopsies can reveal the presence of blasts in both the bloodstream and bone marrow tissue.

Unlike other types of leukemia, ALL is also associated with a chromosomal translocation called the Philadelphia chromosome, where genetic information on one chromosome swaps places with information on another. Adults with ALL are more likely to have the Philadelphia chromosome.

Acute Lymphocytic Subtypes

Acute lymphocytic leukemia has three subtypes:

  • L1 is the most common subtype of acute lymphocytic leukemia, distinguished by small lymphocytes
  • L2 has larger lymphocytes and accounts for 10 percent of ALL cases, as reported by the American Cancer Society (2009).
  • L3 is the most uncommon subtype.

Further classification depends on where the cancer originated, which is determined through immunophenotype testing. The Mayo Clinic (2008) states that approximately 85 percent of ALL cases begin in B lymphocytes, while the remaining 15 percent being in T lymphocytes. This distinction is necessary to ensure proper treatment.

Acute Lymphocytic Leukemia Survival Rates

The overall prognosis for ALL is very positive, as compared to other types of leukemia: 80 percent of children with acute lymphocytic leukemia are disease-free for five years after treatment, according to the National Cancer Institute. Prognosis is less positive in adults, as well as children with the following:

  • Cancer that spreads to the brain and spinal cord
  • Chromosomal abnormalities
  • High white blood cell counts at diagnosis.

Resources

American Cancer Society. (2007). How is childhood leukemia classified? Retrieved March 22, 2010, from http://www.cancer.org/docroot/CRI/content/CRI_2_4_3X_How_is_childhood_leukemia_staged_24.asp?rnav=cri.

American Cancer Society. (2009). What are the key statistics about acute lymphocytic leukemia? Retrieved March 22, 2010, from http://www.cancer.org/docroot/CRI/content/CRI_2_4_1X_What_Are_the_Key_Statistics_About_Acute_Lymphocytic_Leukemia.asp?sitearea=.

American Cancer Society. (2009). What are the key statistics about childhood leukemia? Retrieved March 26, 2010, from http://www.cancer.org/docroot/CRI/content/CRI_2_4_1X_What_are_the_key_statistics_about_childhood_leukemia_24.asp.

American Cancer Society. (2007). What is childhood leukemia? Retrieved March 22, 2010, from http://www.cancer.org/docroot/CRI/content/ CRI_2_4_1X_What_is_childhood_leukemia_24.asp?sitearea=.

Children’s Hospital Boston. (n.d.). Acute lymphoblastic leukemia. Retrieved April 28, 2010, from http://www.childrenshospital.org/az/Site759/mainpageS759P0.html.

Mayo Clinic Staff. (2008). Acute lymphocytic leukemia. Retrieved March 22, 2010, from http://www.mayoclinic.com/print/acute-lymphocytic-leukemia/DS00558/DSECTION=all