CML: epidemiology, etiology & pathophysiology

CML is an abbreviation for chronic myelogenous leukemia. This is a form of leukemia that accounts for approximately 20% of all leukemia forms. The disease takes place in the bone marrow and is dormant. The complaints are not always clearly identifiable and approximately 50% of CML cases are discovered by chance. The disease is mainly diagnosed in people over 50. which organs are actually responsible for CML? How often does it occur and how does CML actually develop?


CML is approximately twice as common in men than in women and approximately 200 new cases of chronic myelogenous leukemia (CML) are diagnosed in the Netherlands every year. I have calculated the prevalence of people with CML (national, 5-year prevalence in 2012) and this shows that there are approximately 1035 people with CLM living in the Netherlands. The incidence concerns 169 people in 2011. Approximately 20% of all leukemia patients are affected by CML. Approximately 249 people die per year (in 2012) and approximately 25% of CLM patients are still alive after 5 years. After 10 years, this percentage is only around 10%. What is striking is that the survival rate is higher in the period 2006-2010. This may indicate an improvement in treatment. It rarely occurs in children.


Philadelphia syndrome is a protein chromosome. It is a mutated chromosome in which parts of chromosomes 9 and 22 have been joined together. Research has shown that CML patients have this abnormality and these chromosomes cause too many and/or abnormal development (immature) of the white blood cells. However, Philadelphia syndrome also occurs in Acute Lymphocytic Leukemia (ALL). In CML, the Philadelphia syndrome occurs in approximately 95% and in ALL this is not always the case.

Because there is a high production of white blood cells in the bone marrow, there is less room for other blood cells such as red blood cells, etc. The result is that the patient feels very tired. Red blood cells contain hemoglobin and a shortage of red blood cells (and hemoglobin) causes an iron deficiency and makes the patient look pale. The bruising that occurs with CML may be due to the iron deficiency.

The weight loss may be the result of the growing spleen, which causes the stomach to become oppressed. The stomach is smaller, so less can fit in it. Weight loss may also be related to an increased metabolism. It may be that the leukemia cells require more fuel.

It is not known exactly what causes Philadelphia syndrome (perhaps due to radioactive radiation), but one thing is certain, CML is not hereditary. Chronic Myeloid Leukemia can also turn into Acute Myeloid Leukemia. In this case the treatment is more severe. The difference between chronic and lymphocytic leukemia is that the origin of the cells is different. In lymphocytic leukemia it comes from the immature lymphocytes and in Myeloid leukemia it comes from the immature myeloid cells.



The spleen ensures that the blood is purified and therefore has two types of tissues; the red pulp and the white pulp. The red pulp removes waste products from the blood and the white pulp kills bacteria and viruses. The older you get, the more your spleen shrinks. In diseases such as leukemia, the spleen pumps itself full and can cause stabbing pain.

Bone marrow

The bone marrow is also soft tissue in the cavities of some bones and can be divided into two types of bone marrow. The red bone marrow (responsible for the production of new blood cells) and the yellow bone marrow (replaces the red bone marrow after the age of 5). The yellow bone marrow can also be converted back into red bone marrow. The bone marrow is responsible for the production of red and white blood cells and also for the production of platelets.

Red blood cells

The majority of all blood cells in the blood consist of red blood cells (99%). These cells are responsible for transporting oxygen and removing carbon dioxide. The color of the blood cell is due to the hemoglobin that is part of the cell. Hemoglobin contains iron.

White blood cells

White blood cells can also be divided into different types of white blood cells. For example, one species tackles bacterial infections and other inflammatory reactions, while the other species combats parasitic infections. White blood cells are also responsible for making antigens and for an allergic response, attacking and digesting invaders.


Blood sites cannot really be labeled as blood cells, but they do have an important function in terms of clotting. When you have a wound, the platelets also ensure that a web is created that stops passing blood cells and thus ensures that the wound is closed (the scab).