What is CML?
  1. What is CML?

What is CML?

Chronic myeloid leukemia (CML) is a form of blood cancer. Another word for blood cancer is leukemia. It is called chronic because the disease usually develops slowly and will not disappear.

What causes CML?

CML is caused by a change in the genetic material (DNA) of the stem cells in the bone marrow. Stem cells are the ‘seeds’ that grow into blood cells. DNA consists of chromosomes; these chromosomes are formed by genes.

CML Philadelphia chromosome
Philadelphia chromosome


In CML cells, part of a chromosome (number 9) has switched places with part of another chromosome (number 22). This new chromosome is called the Philadelphia chromosome.

BCR-ABL gene

The exchange between the chromosomes creates a new gene, called the BCR-ABL gene. This is a coupling of the gene called ABL from chromosome 9 with the gene called BCR from chromosome 22. The BCR-ABL gene causes the production of the BCR-ABL protein, which causes bone marrow cells to divide far too much. This in turn causes the creation of too many white blood cells that will use the blood to roam through the body.

From life-threatening to chronic

Since the launch of the medicine imatinib in 2001, physicians have made great progress in the treatment of CML. The disease has changed from a life-threatening disease to a condition that can be kept under control in most patients, with a nearly normalized survival rate.

CML is not hereditary

The problem with CML lies only in stem cells and not in reproductive cells; this means that CML is not hereditary and cannot be passed on to children.