What is Chronic myeloid leukemia :
The white blood cells are the cells involved in the body’s defense. Within find different types of leukocytes such as polymorphonuclear leukocytes, lymphocytes or monocytes, each with a specific function within the immune system.
Leukocytes originate in the bone marrow cells from immature blasts that are known to create differentiating different types of leukocytes. When this occurs, for different reasons, a loss of control mechanisms of proliferation of these white blood cells of leukemia speech, cancer blasts leukocytes and their precursors.
Depending on the type of blasts in leukemia involving lymphatic leukemias are distinguished, if involved lymphoblasts, precursors of lymphocytes, or myeloid leukemias, whether they are the precursors of red blood cells, platelets and leukocytes from other cells that cause cancer.
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Also, depending on your establishment and the proportion of mature and immature cells involved in leukemia, it may be acute, with a predominance of immature forms and rapid evolution, or chronic, with a greater number of mature cells and slower progression.
Therefore, when a patient suffers from a hematologic cancer cells where there is a predominance of mature leukocytes (except lymphocytes) will be classified as such pathology chronic myeloid leukemia.
How does it occur ?
Chronic myeloid leukemia mainly affects middle-aged people and is known to be associated with a specific genetic alteration, however it is unknown what may be the cause or causes that can trigger such alteration.
Chromosomes consist of two regions that differ in size, called short arms and long arms. When the short arm of chromosome 22 was cleaved from the rest of the chromosome and chromosome 9 are attached, forms a new structure called the Philadelphia chromosome. It has been shown that such alteration in 95% of cases in the cells of patients with chronic myeloid leukemia.
Noticing this alteration are contacted two oncogenes, ie two genes that altering processes can trigger cancer. Together give rise to a protein that stimulates cell proliferation of myeloblasts, the precursors do not lymphocytes mainly leukocytes, although the protein can also act on the precursors of erythrocytes and megakaryocytes. Likewise, said chromosome can be also up to 20% of B lymphocytes
When this protein activated cellular proliferation of myeloblasts, the cells begin to reproduce and fill the marrow space, displacing the remaining healthy cell lines, which have less space to proliferate. Cancerous leukocytes pass into the blood and from there can colonize other organs, especially lymph nodes, liver and spleen.
Chronic myeloid leukemia Symptoms
Initially most patients usually do not present any symptoms and as the disease progresses down a toxic syndrome characterized by fatigue, weakness, weight loss and anorexia.
When come to the blood leukocytes tend to invade the lymph, which is common for patients presenting lymphadenopathy. Also, in most cases there is hepatomegaly and splenomegaly by the same invasion of leukocytes.
As the disease progresses the proliferation of leukocytes is accelerated and immature forms begin to appear in the blood is what is called accelerated phase of chronic myeloid leukemia. 80% of patients spend at this stage, which increase both splenomegaly and hepatomegaly malignant cells can infiltrate tumors giving other peripheral tissues.
Later, already established phase transformation, as immature cells are invading the bone marrow and occupy more than 50% of the tissue or blood presence in more than 30%, it enters what is called blast crisis for at that moment are immature cells, blasts, incumbents.
Up to 60% of patients with chronic myeloid leukemia rapidly progresses to the blastic phase without going through the phase transformation. At this stage there is a malaise, it accelerates weight loss, you lose the appetite and increases fatigue. The worsening anemia, which contributes to the worsening of the patient. It also tends to increase the size of liver and spleen, a fever, bone pain, and there can sometimes be broken.Most blastic phases give rise to acute myeloid leukemia, but up to 25% of cases may be acute lymphocytic leukemia.
In addition to anemia, due to the alteration of leukocytes and the decrease in platelet levels appear severe infections and bleeding processes.
Exceptionally transformation of chronic leukemia, acute phase, ie, the proliferation of immature forms can occur which are found in leukocytes colonize other organs and not in the bone marrow. If that happens, the tumors formed by mieoloblastos occurring in these organs are called chloromas.
Chronic myeloid leukemia Diagnosis
The diagnosis of chronic myeloid leukemia based on blood tests and bone marrow biopsy. In a number of cases the diagnosis was made by an incidental finding of elevated levels of leukocytes to perform a blood test. In the same analysis can detect a decrease in both platelets and red cells in advanced stages.
Chronic myeloid leukemia should be suspected in elderly patients who present a picture of tiredness, weakness and weight loss and anorexia without other apparent cause. It should also be noted as diagnosis in patients or relate to explore one enlarged liver, spleen, or both.
The blood tests will be appreciated an increase in the total numbers of leukocytes and a normochromic normocytic anemia (red cells of normal size and amount of normal hemoglobin) and without elevated blood reticulocytes, the precursor forms of red blood cells , a fact that indicates that bone marrow can not respond to anemia be affected. Platelets can be decreased as much high. In the blast phase was observed over 30% myeloblasts in blood.
Confirmation of the diagnosis provide the bone marrow biopsy, in which it will be appreciated an increase in cellularity, especially at the expense of the myeloid cells. In the processing steps and the number of myeloblasts blastic be significantly increased, exceeding 50%. Genetic methods exist to determine the presence of malignant cells in the Philadelphia chromosome.
Imaging tests such as computed tomography (CT) and ultrasound allow assessing the presence or absence of lymph node, liver, spleen or other locations.
Chronic myeloid leukemia Treatment
The only curative treatment exists is bone marrow transplantation. All other treatments are palliative chemotherapy using. If you can not obtain transplant opt for treatment with interferon. In case of severe anemia should be transfused to the patient.
Worse prognosis factors are advanced age, severe anemia, splenomegaly giant, the largest number of leukocytes and platelets in the blood, a high percentage of blasts and the absence of the Philadelphia chromosome.
Precautions
Given the unknown origin of chronic myeloid leukemia, despite the proven relationship with the Philadelphia chromosome mutation, there are no preventive measures against it.