Leukemia is a type of cancer affecting body’s white blood cells. The disease is characterized by abnormal and uncontrolled production of white blood cells. There are two variants of leukemia; myeloid leukemia and lymphocytic leukemia. This depends on the type of white blood cells involved. Myeloid leukemia occurs when the white blood cells in bone marrow are affected. In lymphocytic leukemia white blood cells (lymphocytes) present in lymph fluid and lymph node are affected.
In myeloid leukemia abnormality occurs in monocytes, a type of white blood cells. Chronic myeloid leukemia (CML) is a slow progressing blood cancer.The disease mainly occurs in older people. Children are rarely affected. The symptoms of CML are easy bleeding, loss of weight, loss of appetite, pain under ribs, pale skin, fever etc.
Chronic myeloid leukemia is caused by mutation in genes. Treatment consists of chemotherapy, targeted drugs and bone marrow transplant to achieve long term remission of the disease.
What Is The Cause Of Chronic Myeloid Leukemia?
Chronic myeloid leukemia is caused due to acquired mutation in genes. The exact cause of initial genetic defect is not known. Abnormality arises in genes that control the growth of blood cells.The changes that follow will result in abnormal growth of cells. When it is an acquired mutation, something goes wrong during the lifetime and it is not passed on from parents. Human beings have 23 pairs of chromosomes. In chronic myeloid leukemia there is translocation between chromosome 22 (BCR) and chromosome 9 (ABL). This causes long chromosome 9 and short chromosome 22. The short chromosome is known as Philadelphia chromosome which is present in almost all patients suffering from chronic myeloid leukemia.
The genes from both this chromosomes get together to form an abnormal gene called BCR-ABL gene. This mutated gene enables the specific white blood cells to multiply uncontrollably leading to development of chronic myeloid leukemia. The abnormal immature white cells occupy large space in bone marrow which causes crowding and reduction in formation of other cells such as red blood cells and platelets as well as normal white blood cells. The disease is usually present in older people. It has male predominance. Exposure to radiation is another key risk factor.
Signs And Symptoms Of Chronic Myeloid Leukemia
In chronic myeloid leukemia there is abnormal multiplication of monocytes, basophils, neutrophils and eosinophils in the bone marrow and blood. Eventually it spreads to other areas of the body. They take over excessive space in bone marrow and reduce production of other blood cells such as red blood cells, platelets, and normal white blood cells. Thus gives rise to various symptoms.
In the initial stage chronic myeloid leukemia is rarely diagnosed because patient may have vague symptoms. During this phase, the white blood cells are still healthy and they are able to fight any infection. As the disease progresses symptoms become more prominent.
- Patient may have pain in left upper side of abdomen and below the left lower ribs. This is because of enlargement of spleen. The spleen gets enlarged because of too many leukemic cells in spleen.
- Enlarged spleen can put pressure on the stomach giving rise to sensation of fullness and loss of appetite.
- Over a period of time as the normal white cells becomes less, patient may get frequent infections.
- Reduced red blood cells will cause anemia, fatigue, shortness of breath, skin and conjunctiva pallor.
- Reduced platelets in bone marrow and in the blood will lead to easy bleeding for no apparent reason, tiny hemorrhagic spots under skin of lower leg, repeated bleeding from nose, and gums.
- Unintentional weight loss.
- Too much of sweating at night.
Diagnosis And Treatment Of Chronic Myeloid Leukemia
Generally in the initial stage chronic myeloid leukemia does not produce any significant symptoms. This blood cancer is often detected on routine blood examination. The symptoms present if any are those that may be present even in other types of diseases. These symptoms may be fatigue, fever, swollen spleen etc. When abnormal cells are detected during normal blood examination, the doctor will recommend further tests such as bone marrow aspiration. The aspirated material is sent to laboratory for testing.
In chronic myeloid leukemia patient has abnormal high count of white blood cells, especially neutrophils, eosinophils and monocytes. Patient also has anemia. Special tests for presence of Philadelphia chromosome may be used. These tests are FISH and PCR of the bone marrow samples.
Once chronic myeloid leukemia is confirmed, the goal of treatment is to kill the abnormal cells containing BCR-ABL gene. They are the culprits to cause excessive number of abnormal white cells in the bone marrow. Following therapies are beneficial:
- Targeted therapy is suitable for treatment of this condition. The drugs used specially act and block the protein that is manufactured by BGR-ABL gene. Targeted therapy is found to be successful in treating the condition.
- Chemotherapy is used to kill the abnormal cancer cells. In chemotherapy the drugs used have many side effects. The medicine used is able to kill the abnormal cells but in the course even healthy cells are affected.
- Bone marrow transplant is used only when all other measures fail. This therapy has definite chances of cure but it also has serious risks because during the process, a large dose of chemotherapy is used to kill blood cells in bone marrow. Then the collected blood cells from donor are introduced into the bloodstream. The new cells introduced form healthy blood cells. They replace the diseases cells.