what is leukaemia | What is acute lymphoblastic leukemia?

What is acute lymphoblastic leukemia?

Acute lymphoblastic leukemia (LAL) is a cancer that originates in blood stem cells. Stem cells are basic cells that transform into different types of cells that have distinct functions. By developing, the blood stem cells become blastic cells (blasts), which are immature blood cells. In the case of leukemia, there is an overproduction of blastic cells. These blastic cells develop abnormally and do not become mature blood cells. Over time, blastic cells take the place of normal blood cells, preventing them from performing their tasks. When diagnosed with leukemia, these blastic cells can be called leukemic cells.

There are many different types of leukemias. They are first classified according to the type of blood stem cell from which they develop. Blood stem cells become lymphoid stem cells or myeloid stem cells.

Lymphoid leukemia (also known as lymphoblastic leukemia) originates in abnormal lymphoid stem cells. Lymphoid stem cells are normally transformed into lymphocytes, a type of white blood cell. Lymphocytes are found in the blood and various parts of the lymphatic system, including lymph nodes and spleen. The 3 types of lymphocytes are B lymphocytes, T lymphocytes, and natural killer cells (NK). Lymphocytes help fight infections and destroy abnormal cells.

The types of leukemia are then subdivided according to the speed at which the disease develops and evolves. Acute leukemia starts suddenly and develops in a few days or weeks. Chronic leukemia generally develops slowly over the course of months or even years.

LAL originates in abnormal lymphoid stem cells and evolves rapidly. This is the type of leukemia most frequently diagnosed in young children and it affects boys more often than girls. Of the 4 major types of leukemia that occur in adults, LAL is the least common type. In about 25% of adults with LAL, leukemic cells are carriers of the Philadelphia chromosome (Ph). It is a chromosomal anomaly acquired, which means it occurs at some point after birth.