Chronic Myeloid Leukemia (CML) Information

What Is Chronic Myeloid Leukemia?

Also known as chronic myelogenous leukemia, chronic myeloid leukemia is a form of cancer that affects the bone marrow and blood. It begins in the blood-forming cells of the bone marrow and then, over time, spreads to the blood. Eventually, the disease spreads to other areas of the body.

Typically, being categorized as chronic indicates that this type of leukemia spreads and grows slowly. However, chronic myeloid leukemia can change from slow progressing into a rapidly growing, acute form of leukemia that can spread to almost any organ in the body.

Chronic Myeloid Leukemia Statistics

According to the American Cancer Society, there were approximately 5,050 chronic myeloid leukemia incidences in the United States in 2009. Chronic myeloid leukemia accounts for 10 to 15 percent of all types of leukemia, with the average age of diagnosis being 67.

Understanding CML

Unlike the three other main types of leukemia, chronic myeloid leukemia has a significant difference that sets it apart from the rest. It has been shown that chronic myeloid leukemia is associated with an abnormal chromosome known as the Philadelphia chromosome (Ph chromosome).

Chromosomes are structures in cells that contain genes, which give instructions to the cells. The Ph chromosome is an abnormality that occurs when a piece of chromosome 22 breaks off and attaches to the end of chromosome 9, which also breaks off and attaches to chromosome 22.

The breaks in both chromosomes cause the BCR and ABL genes, which combine to create the cancer gene. The link between the Ph chromosome and chronic myeloid leukemia was discovered around 1960.

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