There are different types of cancers that affects patients around the world. One such cancer is leukemia. This cancer occurs in the bone marrow that helps in formation of blood. Thus, a person with leukemia suffers from production of abnormal white blood cells. These abnormal cells are called leukemia cells. These cells do not proliferate like normal blood cells and they tend to crowd the bloodstream. Thus, the number of normal blood cells decreases leading to many health complications. There are different types of leukemia, that will be discussed in the following Buzzle paragraphs.

Types of Leukemia
Based on Proliferation
The first division of leukemia is according to its acute and chronic form.

Acute Leukemia
This type of 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 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
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 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.

Acute leukemia must be treated immediately, chronic forms are sometimes monitored for some time before treatment to make sure maximum effectiveness of therapy.

Based on Kind of Blood Cell Affected
The disease is classified according to the type of abnormal cells found in the blood.

Lymphocytic leukemia
Also called, lymphoblastic leukemia, it occurs when the B cell lymphocytes turn become abnormal and lead to leukemia.

Myelogenous Leukemia
Myeloid leukemia or myelogenous leukemia is a type of cancer that occurs in red blood cells and sometimes affects the white blood cells as well as platelets.

Based on the Above Two Groups
The above two groups forms the bases of the four main kinds of leukemia's. These types of leukemia may further have more subcategories, but the main types are as follows:

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 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.

Acute myelogenous leukemia
Also known as acute myeloid leukemia or (AML) occurs more commonly in adults than in children. This was previously called acute nonlymphocytic leukemia.

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

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

Hairy cell leukemia (HCL)
This leukemia is generally a subset of chronic lymphocytic leukemia. It mostly affects adult men and is incurable. However, there are treatments that help control the proliferation of this cancer.

Large granular lymphocytic leukemia
The T-cells or NK cells are involved and is a very rare type of leukemia. This rare cancer is not very aggressive, therefore treatment is successful in most cases.

T-cell prolymphocytic leukemia (T-PLL)
This is a very rare form of leukemia that is really aggressive in nature. It affects adults and involves mature T cells. This is very difficult to treat and survival rate is poor.

Adult T-cell leukemia
The human T-lymphotropic virus (HTVL) (type of virus), can affect the CD4+ T-cells. This causes them to replicate and proliferate abnormally leading to adult T-cell leukemia.

Causes of Leukemia
Leukemia is like other cancers, resulting from somatic mutations in the DNA which activate oncogenes or deactivate tumor suppressor genes, and disrupts 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.

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

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.

This was all about the types of leukemia and some of the possible causes of this grave disease. These can be controlled, of caught during their early stages. For more information, speak to a specialist for detailed explanation.