Precursor B-cell lymphoblastic leukemia is a form of

lymphoid leukemia Lymphoid leukemias are a group of leukemias affecting circulating lymphocytes, a type of white blood cell. The lymphocytic leukemias are closely related to lymphomas of the lymphocytes, to the point that some of them are unitary disease entities t ...

in which too many

B-cell B cells, also known as B lymphocytes, are a type of the lymphocyte subtype. They function in the humoral immunity component of the adaptive immune system. B cells produce antibody molecules which may be either secreted or inserted into the plasm ...

lymphoblasts (immature

white blood cells White blood cells (scientific name leukocytes), also called immune cells or immunocytes, are cells of the immune system that are involved in protecting the body against both infectious disease and foreign entities. White blood cells are genera ...

) are found in the

blood Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood is com ...

and

bone marrow Bone marrow is a semi-solid biological tissue, tissue found within the Spongy bone, spongy (also known as cancellous) portions of bones. In birds and mammals, bone marrow is the primary site of new blood cell production (or haematopoiesis). It i ...

. It is the most common type of

acute lymphoblastic leukemia Acute lymphoblastic leukemia (ALL) is a cancer of the Lymphocyte, lymphoid line of blood cells characterized by the development of large numbers of lymphoblast, immature lymphocytes. Symptoms may include feeling tired, pale skin color, fever, ...

(ALL). It is sometimes additionally classified as a lymphoma, as designated ''leukemia/lymphoma''. ALL is the most prevalent childhood malignancy, with precursor B-cell ALL (B-ALL) accounting for approximately 75–80% of newly diagnosed pediatric ALL cases.

Subtypes

It consists of the following subtypes: * t(9;22)-BCR/ ABL * t(v;11q23)-MLL rearrangement * t(1;19)-E2A/PBX1 * t(12;21)-ETV/ CBFα
t(17;19)-E2A-HLF

Molecular mechanisms

One interesting model of precursor B ALL shows aberrant function of a single gene, namely Pax5, as capable to change phenotype of B cells toward precursor cells. In approximately two-thirds of pediatric B-ALL patients, specific chromosomal translocations and their fusion genes are detectable, and these fusion genes play crucial roles as risk factors for strategic treatment. More than 200 fusion genes or mutated genes have been identified in ALL patients to date.

Diagnosis

t(12;21)-ETV/ CBFα has a better prognosis as compared to other subtypes.

Treatment

References

External links

Precursor B-lymphoblastic leukemia
entry in the public domain NCI Dictionary of Cancer Terms {{Hematological malignancy histology Acute lymphocytic leukemia