Leukemia is a type of cancer that affects the blood cells and the bone marrow. This cancer usually begins in the bone marrow and undergoes a leukemic change which means, the cell might grow and survive better than normal cells. As a result, the cells suppress the growth and development of normal cells which might disrupt bodily functions and cause life-threatening symptoms.

The rate at which the disease progresses depends on how the leukemic cells replace normal bone marrow and blood cells. Following are some types leukemia based on the type of cells:

Acute lymphoblastic leukemia (ALL)
It is a type of cancer of blood and bone marrow that progresses due to acquired or genetic injury of the DNA while stem cells are developing in the bone marrow. Although acute lymphoblastic leukemia (ALL) starts in the bone marrow and stems cells, it can progressively spread to the central nervous system, lymph nodes, and in some cases, testicles.

Acute myeloid leukemia (AML)
This type of cancer usually develops in bone marrow and develops acquired mutation. Acute myeloid leukemia (AML) affects red blood cells, white blood cells, and platelets. As a result, the number of healthy blood cells is usually lower than normal. The decrease in the count of all the three types of blood cells is called as pancytopenia.

Chronic lymphocytic leukemia (CLL)
It affects lymphocytic cells and is typically a slow-growing disease as many people with this type of cancer don’t exhibit symptoms for years. Chronic lymphocytic leukemia (CLL) most often affects older adults. The average age of diagnosis is about 70 years. Researchers have also found that there is a potential association between CLL and herbicides like Agent Orange used during the Vietnam conflict from 1961 to 1971.

Hairy cell leukemia (HCL)
It is a rare type of blood cancer which gets its name from the short and thin projections present on its cells. Although rare, people suffering from this type of cancer usually live a good quality of life with proper medical care. Hairy cell leukemia (HCL) usually affects B lymphocytes that produce antibodies to fight infections. The cells also tend to accumulate in the bone marrow, liver, and spleen.

Chronic myelomonocytic leukemia (CMML)
This type of leukemia is an uncommon form of blood cancer that has similar signs and symptoms of two other types of cancer. It affects stem cells and progresses ahead to infect monocytes, a type of white blood cell. Chronic myelomonocytic leukemia (CMML) reduces the immune system’s ability to guard against the infections. It also reduces the number of neutrophils in the blood leading to a condition called as leukopenia. The low number of platelets cause bleeding and bruising with no apparent cause.

Juvenile myelomonocytic leukemia (JMML)
This type of cancer is commonly diagnosed in children and infants younger than five years. Similar to CMML, it affects both neutrophils and monocytes. Juvenile myelomonocytic leukemia (JMML) forces monocytes to multiply uncontrollably and crowd out white blood cells, leading to a reduction in immunity. JMML leads to complications such as anemia, neutropenia, thrombocytopenia.

Large granular lymphocytic leukemia (LGL)
It is a type of chronic leukemia which affects the blood cells called “lymphocytes,” which govern the body’s immune system and fight against certain infections. As the name suggests, large granular lymphocytic leukemia (LGL) is characterized by enlarged lymphocytes and noticeable granules. LGL affects both men and women equally and the median age of diagnosis is 60 years. There are two types of LGL, namely, T-cell and NK-cell leukemia which results in the enlargement of spleen and liver.

Blastic plasmacytoid dendritic cell neoplasm
Previously known as natural killer (NK) cell lymphoma or leukemia, the World Health Organization (WHO) characterizes it under AML. This type of leukemia affects white blood cells, spleen, and platelets. The lymph nodes might also be affected but might not exhibit any symptoms.

B-cell prolymphocytic leukemia (B-PLL)
A rare and aggressive form of malignancy, B-cell prolymphocytic leukemia (B-PLL) is characterized by uncontrollable growth of B-lymphocytes, type of white blood cells supporting the immune system. The median age of getting diagnosed with B-PLL is 70 years, and it is more common in men than women. B-PLL can also occur due to the slow transformation or progression of CLL. The signs and symptoms of B-PLL include an enlarged spleen, high lymphocyte count, anemia, and thrombocytopenia (low platelet count).

T-cell prolymphocytic leukemia (T-PLL)
An extremely rare and aggressive form of malignancy, T-cell prolymphocytic leukemia (T-PLL) is characterized by out of control growth of T-lymphocytes (T-cells). T-cells are a type of white blood cells that protect the body from infections. The median age of diagnosis is 60 years and it usually affects men more than women. Medical researchers regard chromosomal abnormalities as the main cause of getting infected from T-PLL. If left untreated, this form of leukemia grows and multiplies, leading to enlargement of the liver, spleen, and in some cases, lymph nodes.