Leukemia is the most common blood cancer that majorly affects people who have crossed the age of 55. However, it is also the most common kind of cancer affecting children under the age of 15. 

Here we will look at some of the most common types of leukemia.

Acute lymphocytic leukemia (ALL)
Acute lymphocytic leukemia is one of the most common types of leukemia. This type of leukemia occurs in the immature white blood cells, the B or T lymphocytes. These cells are an essential component of the immune system, as they are the building blocks of the lymphoid tissues. Acute lymphocytic leukemia can spread to the liver, spleen, and lymph nodes. It can also affect the bone marrow. ALL can further be sub-classified based on the developmental stage and a variety of lymphocytes involved.

Chronic lymphocytic leukemia
Chronic lymphocytic leukemia develops when lymphocytes crowd normal blood cells, so it becomes difficult to fight infection. Chronic lymphocytic leukemia majorly affects the older adults, and the progression of this condition is gradual and slow. So much so that the symptoms may appear years after the occurrence of this medical condition. Its onset begins in type B lymphocytes. These lymphocytes are present in the bone marrow and then extend in the blood. Moving forward, it may also spread to organs, such as the spleen, liver, and lymph nodes.

Hairy cell leukemia (HCL)
Also known as HCL, this is a sub-type of chronic lymphocytic leukemia, and this condition is rare. It is a type of leukemia that grows slowly. It gets its name from how the cells look under the microscope. Cells look as if they have minute hair-like fragments. It occurs when the bone marrow starts generating too many lymphocytes (B cells). The number of men affected by hairy cell leukemia is higher than that of women. The reason it falls under the category of chronic disease is that it may never disappear completely.

Acute myeloid leukemia (AML)
Yet another common type of leukemia is acute myeloid leukemia (AML). It is a fast-growing cancer of the bone marrow and the blood. AML occurs when the bone marrow begins to develop cells that have not completely matured. Such cells do not develop and, as such, are unable to fight infections. In AML, the bone marrow also makes abnormal platelets and red blood cells. One thing that differentiates AML from other kinds of leukemia is that it further has eight different sub-categories, which are based on those cells from which leukemia developed.

Though there are no screening tests for leukemia, doctors often discover it through routine blood tests. They may even have to depend on their existing knowledge of the disease and experience. If a doctor suspects the chances of leukemia, he or she may prescribe bone marrow biopsy, spinal tap, or blood tests.