Types of Leukemia

What is Leukemia?
It is like other cancers, result from somatic mutations in the DNA which activate oncogenes or deactivate tumor suppressor genes, and disrupt the regulation of cell death, differentiation or division. These mutations may occur spontaneously or as a result of exposure to radiation or carcinogenic substances and are likely to be influenced by genetic factors. Cohort and case-control studies have linked exposure to petrochemicals, such as benzene, and hair dyes to the development of some forms of leukemia.

Types of Leukemia:
1. Acute lymphocytic leukemia (Also known as Acute Lymphoblastic Leukemia or ALL) is the most common type of leukemia in young children. This disease also affects adults, especially at age 65 and older. This type of Leukemia is a cancer of the white blood cells, characterized by the overproduction and continuous multiplication of malignant and immature white blood in the bone marrow. It is a hematological malignancy.

2. Acute myelogenous leukemia (also known as Acute Myeloid Leukemia or AML) occurs more commonly in adults than in children. This type of leukemia was previously called acute nonlymphocytic leukemia.

3. Chronic lymphocytic leukemia (CLL) most often affects adults over the age of 55. It sometimes occurs in younger adults, Children are never affected by CLL.

4. Chronic myelogenous leukemia (CML) occurs mainly in adults. A very small number of children also develop this disease. This type of leukemia characterized by increased and unregulated clonal production of predominantly myeloid cells in the bone marrow.

Leukemia is clinically and pathologically split into its acute and chronic forms.

Acute leukemia is characterized by the rapid growth of immature blood cells. This crowding makes the bone marrow unable to produce healthy blood cells. Acute forms of leukemia can occur in children and young adults. (In fact, it is a more common cause of death for children in the US than any other type of malignant disease). Immediate treatment is required in acute leukemia’s due to the rapid progression and accumulation of the malignant cells, which then spill over into the bloodstream and spread to other organs of the body. If left untreated, the patient will die within months or even weeks.

Chronic leukemia is distinguished by the excessive build up of relatively mature, but still abnormal, blood cells. Typically taking months to years to progress, the cells are produced at a much higher rate than normal cells, resulting in many abnormal white blood cells in the blood. Chronic leukemia mostly occurs in older people, but can theoretically occur in any age group.

Whereas acute leukemia must be treated immediately, chronic forms are sometimes monitored for some time before treatment to ensure maximum effectiveness of therapy.

Furthermore, the diseases are classified according to the type of abnormal cell found most in the blood.

When leukemia affects lymphoid cells (lymphocytes and plasma cells), it is called lymphocytic leukemia.

Causes of Leukemia:
The causes of Leukemia are not defined in general, as the causes of leukemia are different for different types of Leukemia. Researchers have strong suspicions about four possible causes:
i) natural or artificial ionizing radiation
ii) certain kinds of chemicals
iii) some viruses
iv) genetic predispositions

Regular and unprotected exposure to some chemicals can lead to the development of leukemia. However, exposure to chemicals while on the job is the cause of the leukemia. Persons with Down syndrome are also at a greater risk of developing leukemia than the general public. Anyone who has received chemotherapy treatments as treatment for another form of cancer is also much more likely to develop leukemia than a person who has never received chemotherapy treatments. Persons who suffer with the blood disease known as Myelodysplastic syndrome may also find themselves with a diagnosis of leukemia as a natural progression of their condition.

The leukemia specialist will determine the specific type of leukemia that has developed. It is easier to evaluate overall health conditions which come up with a leukemia treatment program that will be right for the leukemia patient. Radiation therapy may be determined to be the best leukemia treatment. For the next person, biological therapy may be seen as the right leukemia treatment.

The main cause of leukemia is the exposure to very high levels of radiation. However, radiation exposure at a nuclear reactor or being exposed to the massive amount of radiation released when an atomic bomb explodes definitely is linked to leukemia.

The fact of the Leukemia is that the viruses have also been linked to some forms of leukemia. Fanconi anemia is also a risk factor for developing leukemia. Until the cause or causes of leukemia are found, there is no way to prevent the disease. Even when the causes become known, they may prove to be things which are not readily controllable, such as naturally occurring background radiation, and therefore not especially helpful for prevention purposes.