A generalized neoplastic disorder of the blood‐forming tissues, primarily those of the leukocyte series.

Cancer of blood-forming tissue.

A progressive, maglinant disease of the blood-forming organs, marked by distorted proliferation and development of leukocytes and their precursors in the blood and bone marrow.

Cancer of the blood and lymphatic systems. There are two kinds of leukemias: a. Acute leukemia, which is most common among children. b. Chronic leukemia, which is most common in adults over 40 years. Death from leukemia usually results from increased susceptibility to infection and hemorrhage. Causes range from exposure to radiation, certain chemicals, and viruses.

A cancer in which white blood cell production is uncontrolled.

A form of cancer that involves unchecked production of white blood cells in the bone marrow. These gradually crowd out the red blood cells and platelets required for health, leading to severe anemia and hemorrhages. In children, leukemia often develops rapidly and, if untreated, can cause death within weeks or months. But a variety of drugs are used to try to halt the process, producing remissions and sometimes full cures.  If relapses occur, physicians may consider a bone marrow transplant, though the operation is risky, and finding a donor with matching bone marrow is difficult. As with cancer in general, the causes of leukemia are obscure, though some forms seem to be triggered by a virus or by environmental hazards such as radiation or individual cancer-causing chemicals (carcinogens). People with some genetic disorders or chromosomal abnormalities, such as Down’s syndrome, are at increased risk for leukemia.

One of the major types of cancer, malignant neoplasm of blood- forming tissues, characterized by abnormalities of the bone marrow, spleen, lymph nodes, and liver and by rapid and uncontrolled proliferation of abnormal numbers and forms of leukocytes (white blood cells). Leukemia may be acute, rapidly progressing from signs of fatigue and weight loss to extreme weakness, repeated infections, and fever, or it may be chronic, progressing slowly over a period of years. Leukemia is usually classified according to the type of white blood cell that is proliferating abnormally. Treatment involves chemotherapy, blood transfusions, antibiotics to control infections, and, sometimes, bone marrow transplants. Also called cancer of the blood.

A cancer that affects the blood-forming system, causing production of large numbers of abnormal white blood cells that invade organs such as the bone marrow, liver, and kidneys. The disease occurs in two forms: acute leukemia, which frequently attacks children, and chronic leukemia, a less severe form that more often affects elderly people.

A malignant, or cancerous, disease that affects the blood-forming cells found in the bone marrow and the lymphatic system. Leukemia results in an abnormally high number of abnormal white blood cells (blasts). The blasts are cells that would normally develop into white blood cells but with leukemia stop short in their development. High concentrations of blasts in the bone marrow, lymph nodes, and bloodstream can impair the function of these tissues. Some types of leukemia may also affect the liver, spleen, or brain. In addition, overproduction of the blasts can crowd out normal cells in the bone marrow and decrease the number of red blood cells, platelets, and normal white blood cells formed by the bone marrow. This can lead to fatigue, weakness, increased bleeding and bruising from slow blood clotting, and a decreased ability to fight infection. Leukemia worsens over time and may result in death if left untreated.

Any of a group of malignant diseases in which the bone marrow and other blood-forming organs produce increased numbers of certain types of white blood cells (leukocytes). Overproduction of these white cells, which are immature or abnormal forms, suppresses the production of normal white cells, red cells, and platelets. This leads to increased susceptibility to infection (due to neutropenia), anemia, and bleeding (due to thrombocytopenia). Other symptoms include enlargement of the spleen, liver, and lymph nodes.

Any of a class of hematological malignancies of bone marrow cells in which immortal clones of immature blood cells multiply at the expense of normal blood cells. As normal blood cells are depleted from the body, anemia, infection, hemorrhage, or death result. The leukemias are categorized as chronic or acute; by the cell type from which they originate; and by the genetic, chromosomal, or growth factor aberration present in the malignant cells.

Cancer of the tissues that make white blood cells.

A cancer of the blood forming tissues in the bone marrow.

Cancers that originate from and spread through the blood-forming systems of the body.

Leukemia is a malignant condition affecting blood cells, wherein there is an abnormal proliferation of white blood cells in the body’s tissues. There exist various types of leukemias, distinguished by the specific variety of white blood cell implicated in the disease.

A condition affecting the blood-forming organs, where there is an uncontrolled growth of white blood cells and an influx of immature white blood cells into the bloodstream in significant quantities. Multiple types of this disease exist, and distinguishing between them is crucial since each has its unique outlook for recovery.