Chronic myeloid leukemia (CML, chronic myelogenous leukemia ) - malignancy that affects hematopoietic bone marrow stem cells. When CML genetic mutations affect the immature version of myeloid cells that produce red blood cells, platelets and most types of white cells (other than lymphocytes). This change leads to formation of abnormal gene BCR-ABL, which converts into healthy cells leukemia. Malignant cells are produced in bone marrow and spread in the body through the bloodstream. Chronic myelogenous leukemia is quite slow growing, but it is able to develop into an acute form of the disease, which is difficult to treat.
For the most part, this disease develops in adults and occasionally in children.
What is leukemia?
Leukemia affects the blood-forming cells in bone marrow. One type of these cells is changing, becoming leukemia, the normal maturation process is disrupted. The fission process is accelerated. Malignant cells do not die as they should. This allows them to accumulate in the bone marrow, crowding out healthy cells. At some point they leave the bone marrow and enter the bloodstream, increasing the number of white blood cells. Once in the blood, abnormal cells are able to spread to other organs, thereby violating the process of their normal functioning.
What is chronic leukemia?
Chronic or acute leukemia depends on the numbers of abnormal cells, which are immature (more like stem cells) and mature (like a healthy white blood cells).
During the chronic mature cells can be partially, but not completely. They resemble normal cells, but is not able to fight infection. Abnormal cells live longer, accumulate and displace healthy bone marrow. For chronic leukemia is quite long before they cause problems, and most of the people live well for many years. But they tend to be harder to treat than acute leukemia.
What is myelogenous leukemia?
Whether myeloid leukemia or lymphocytic depends on which bone marrow cells Cancer affects process.
Myeloid leukemia (also known as myelocytic, myelogenous or Nonlymphocytic) developing in early myeloid cells, which are converted into white blood cells (other than lymphocytes), red blood cells and megakaryocytes.
Slightly more than 10% of all cases of leukemia accounts for chronic myelogenous leukemia. The average age at diagnosis of CML is around '64. Almost half of the cases are diagnosed in people aged 65 years and older.
Risk factors for chronic myelogenous leukemia
Risk factor - external influences, as well as any features or properties of the human body that affect the likelihood of disease. For example, sunlight is a risk factor for skin cancer, smoking - contributes to the emergence of a number of cancer diseases.
Potential risk factors for this disease:
- The effect of high doses of radiation.
- Gender - often the disease develops in men than in women.
On the likelihood of chronic leukemia mielodinogo not affect smoking, diet, chemical exposure or infection, genetics.
Whether the causes of chronic myeloid leukemia are known?
Healthy cells grow and operate mainly on the basis of information contained in the chromosomes, which are long DNA molecules. DNA is the chemical substance in the composition of which genes and instructions on how cells need to function. The similarity of the children and parents due to the fact that parents provide DNA. But genes affect more than people can imagine.
When a cell divides, a new copy of the DNA in the chromosomes. Unfortunately, this process is subject to errors affecting genes in DNA.
Some genes control when cells need to grow and share. Certain genes that promote development are oncogenes. Others, slowing growth to cause cell death at the right time, called suppressor genes. Oncology may be triggered by changes in DNA (mutations) which contribute in converting oncogenes or suppressor genes shutdown.
Over the past few years, scientists have made significant progress in the representation of how DNA mutations contribute to the transformation of healthy cells into leukemia.
Every cell of the human body contains 23 pairs of chromosomes. In general cases of CML are the result of "replacement" chromosomal material between chromosome 9 and 22 during cell division: a part of chromosome 9 minutes out to 22 minutes, and a part 22 minutes - to 9 minutes. This condition is called a translocation, it is the cause of reducing the size of the chromosome 22, this new type of abnormal known as the Philadelphia chromosome. It occurs in pathological cells in virtually all CML patients.
DNA exchange between chromosomes provokes the formation of new gene (oncogene) called BCR-ABL. It produces BCR-ABL protein, which belongs to the type of tyrosine kinase. This protein promotes the growth and uncontrolled proliferation of CML cells.
A very small number of patients abnormal cells contain BCR-ABL protein without the Philadelphia chromosome. It is assumed that the gene they have formed in some other way. In rare cases of CML cells do not have in their composition or the aforementioned gene or Philadelphia chromosome. It is believed that the cause of the disease in a given situation may be unknown oncogenes.
Is it possible to prevent the occurrence of this disease?
Currently there is no known way to prevent the emergence of chronic myeloid leukemia . Many types of malignant diseases may be prevented by lifestyle changes to avoid certain risk factors. In the case of CML disease it can only apply to exposure to high doses of radiation.
Whether diagnosed chronic myeloid leukemia in the initial stage of development?
CML sometimes find when performing routine blood tests in connection with other diseases. Thus revealed elevated levels of white blood cells in the absence of clinical signs. It is important to immediately resort to professional assistance.
Symptoms of chronic myeloid leukemia
Symptoms of CML are often vague, and other causes. These include:
- night sweats;
- loss of body weight;
- pain in bones and joints due to the proliferation of leukemic cells;
- splenomegaly (weight felt on the left side of the chest);
- pain or a feeling of "overcrowding" in the abdomen;
- satiation after drinking even a small amount of food.
However, it is not just the symptoms of chronic myeloid leukemia. They can also occur in other types of cancer and non-malignant diseases.
The problems associated with the shortage of blood cells
Many signs of the disease develops as a result of replacing healthy blood-forming cells in the bone marrow of leukemia.
- Anemia is caused by lack of red blood cells, leading to weakness, fatigue and shortness of breath.
- Leukopenia occurs due to deficiency of healthy white blood cells, which increases the risk of infections. Although patients with leukemia can be a very high level of white blood cells, they can not protect against infection because they are abnormal.
- Neutropenia occurs due to insufficient levels of neutrophils, a type of white blood cells that protect against bacterial infections.
- Thrombocytopenia appears due to lack of platelets. This leads to excessive and unexplained bleeding or bruising. There are frequent or severe nosebleeds, bleeding gums. In some patients with CML platelet count is very high, however, the cells do not function properly.
Diagnosis of chronic myeloid leukemia in Assuta
In many patients with CML have no symptoms at diagnosis. Leukemia is often found when the tests prescribed for other health problems, or in the course of a routine check. Even if symptoms are observed, they are often vague and unspecific.
If there is suspicion of leukemia, the doctor will check the blood samples and bone marrow to be sure of the diagnosis.
Aspiration and bone marrow biopsy in the clinic Assuta
These 2 tests are usually made simultaneously. Samples were taken from the back of the thigh bone, although in some cases the aspiration sample can be taken from the breastbone (sternum).
During aspiration of the patient is placed on the side or stomach. It applies anesthetic local anesthetic. A thin, hollow needle is inserted into the bone, the syringe is removed via a small amount of bone marrow fluid. Even with the anesthetic most people feel some pain.
A biopsy is usually done after the aspiration. Removal of produced pieces and the bone marrow with a special needle larger. This procedure is also able to trigger a brief sensation of pain.
Samples sent to the laboratory, where studied under the microscope leukemic cells. These tests can also be administered after the treatment of cancer in Israel to test the effectiveness of therapy.
For the diagnosis of chronic myelogenous leukemia may be conducted several laboratory tests.
- CBC (complete) measures the levels of different cells - erythrocytes, leukocytes and platelets. In most patients with CML notes the high number of immature white blood cells. Sometimes there is a low number of red blood cells or platelets. Although these findings suggest leukemia, the diagnosis should be confirmed by a blood test or other test exploring the bone marrow.
- Biochemical blood test used to detect disorders of the liver or kidney, leukemia cell proliferation provoked by or resulting from use of certain cytostatics.
- The study of blood samples and bone marrow under a microscope by a pathologist carried out. Studied the size and shape of the cells. Immature cells called myeloblasts or blasts. Count the number of hematopoietic cells in the bone marrow and is called the concept of cellularity. Healthy bone marrow contains hematopoietic and fat cells. When is more than normal hematopoietic cells, it is called hypercellular, if less - Hypocellularity. In patients with chronic myeloid leukemia bone marrow usually hypercellular due to accumulation of the malignant cells.
Genetic testing is used to detect the Philadelphia chromosome and / or gene BCR-ABL.
- Cytogenetics examines the chromosomes (or parts thereof) with a microscope to find any changes. Studied the combination of features set chromosome or karyotype. As better seen in the chromosome during cell division, a sample of blood or bone marrow to be grown in the laboratory. It takes time and is not always successful. Healthy cells contain 23 pairs of chromosomes, each of which has a certain resolution. Leukemic cells in many patients with CML are composed of an abnormal chromosome, known as Philadelphia, which looks like a stripped-down version of chromosome 22. This is due to translocation of parts of chromosome 9 and 22. Detection of Philadelphia chromosome is important in the diagnosis of chronic myelogenous leukemia . Even if it is not detected, other tests are BCR-ABL gene.
- Fluorescence in situ hybridization (method FISH) - another method of chromosome studies. This test uses a special fluorescent dyes, which are attached only to the specific genes, or segments of chromosomes. When looking for a part CML FISH gene BCR-ABL on chromosomes. It is used on samples of blood and bone marrow cells without cultivation, however results are obtained faster than when cytogenetics.
- Polymerase chain reaction (PCR) - a very sensitive test, which is aimed at finding oncogene BCR-ABL leukemia cells. Performed on blood or bone marrow samples and can detect very low levels of BCR-ABL, even when doctors can not find the Philadelphia chromosome in bone marrow cells using cytogenetic testing. PCR was performed for diagnosis of CML and is useful after treatment to check for any copies of the gene. If they are still present, indicating preservation of leukemia, even when the cells are not detected by a microscope.
Imaging methods of diagnosis of chronic myelogenous leukemia
They are not used directly for the production of CML diagnosis. They may appoint, to find the cause of symptoms or increase in organs such as the spleen and liver.
This type of survey will be detected above normal size lymph nodes or other organs. CT can be performed if, for example, a physician suspects leukemia dissemination in the spleen.
Computed tomography - a type of x-ray that produces detailed, layered images of the body, including soft tissue (internal organs). For a more clear contours anomalous zones being received contrast agent in solution or by intravenous infusion. Sometimes CT is used in biopsies.
This is a very useful diagnostic procedure in the study of the state of the brain and spinal cord. Also, it may recommend to explore other areas of the body during the treatment of chronic myeloid leukemia . Instead ray MRI utilizes magnets and radio waves, which absorbs energy of the body, after which it is converted into a very detailed image - not only the cross-sectional slice of the body (as at RT), but in sections, parallel to the length of the body. Less commonly used contrast material.
Ultrasound uses sound waves, which are displayed on the internal organs, creating echoes. This kind of examination in chronic myeloid leukemia is used to examine the lymph nodes located near the body surface, or to find increased intra-abdominal organs - kidney, liver and spleen.