Leukemia, a term that includes several types of this disease, is cancer of the blood. It begins in the cells of the bone marrow, when a normal blood stem cell undergoes a transformation into a malignant cell – one capable of uncontrolled growth.
The four main types of leukemia, which are classified by how quickly they progress and which type of blood cell they develop in, are:
- Acute Myelogenous Leukemia (AML)
- Acute Lymphocytic Leukemia (ALL)
- Chronic Lymphocytic Leukemia (CLL)
- Chronic Myelogenous Leukemia (CML)
In acute leukemias, the bone marrow cells cannot mature properly. These abnormal cells reproduce rapidly, producing immature cells that crowd out normal cells and decrease the formation of new normal blood cells. Acute leukemia tends to progress very quickly over a matter of months.
In chronic leukemias, the abnormal leukemia cells can resemble normal mature cells, but they don’t function correctly. These abnormal cells are unable to fight infection, and also crowd out normal blood cells, often causing anemia. Chronic leukemia progresses more slowly than acute forms.
Although many people think of leukemia as a disease that only affects children, roughly 10 times as many adults are diagnosed with this cancer each year. In all, there are nearly 30,000 new cases of leukemia identified annually in the United States. Chronic lymphocytic leukemia (CLL) and acute myelogenous leukemia (CML) are the most common forms in adults. In children, acute lympoblastic leukemia (ALL) is the most common type.
It’s important to keep in mind that all types of leukemia are treatable, and most are potentially curable.