Leukemia

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Leukemia is type of blood cancer which affects the blood cells usually the white blood cells and bone marrow. White blood cells are integral part of immune system and the bone marrow is where blood cells are made.

People with leukemia have large number of abnormal white blood cells. These abnormal cells develop rapidly and take over the bone marrow. Thus, these become part of blood stream. These cancerous cells also damage the other parts of body such as brain, lymph nodes, spleen and liver etc. Their lifespan is less than normal, healthy cells and the spleen degrades them frequently.

Types of leukemia

Leukemia is of two types:

  • Acute leukemia: It develops faster and spread rapidly
  • Chronic leukemia: The cancerous cell spread slowly than the acute form.

Blood cancer is a vast term and this disease has following types:

  1. Leukemia:  This type of blood cancer occurs in bone marrow. The results are production of abnormal and cancerous white blood cells and platelets. Consequently, this weakens the person’s immune system.
  2. Non-Hodking’s lymphoma: This type of cancer occurs in lymphatic system, in lymphocyte cells. This cell normally helps the body to fight the infections.
  3. Hodking’s lymphoma: This type of blood cancer develops in lymphatic system. This type of cancer has characteristic abnormal cells-lymphocytes. These are also named as Reed-Sternberg cells.
  4. Multiple myeloma:  This type of cancer occurs in blood plasma cells and in bone marrow.

This article covers the leukemic blood cancer.

Signs and symptoms

Symptoms may very form person to person and also their severity is different  in each case and it depends on stage of cancer as well.

  • Fatigue
  • Chest pain
  • Heavy breathing even at rest
  • Bleeding
  • Sudden weight loss and loss of appetite
  • Swollen lymph nodes
  • Enlarged glands such as liver and spleen

Molecular basis and causes of Leukemia

Similar to other forms of cancer, leukemia also happens due to genetic mutation. The mutation in gene results in abnormal and uncontrolled cell divisions. The genetic basis of familial acute myeloid leukemia is mutation in CEBPA gene. This gene codes for a transcription factors which by attaching itself at specific site of DNA, regulate various gene’s expression. Leukemia itself is characterized into various categories based on the gene in which the mutation has occurred. For instance, the genes associated with acute lymphoblastic leukemia are MLLT2, ZNFN1A1, LAF4. On the other hand, genes responsible for chronic lymphocytic anemia are DLEU1 and DLEU2 gene mutations.

These genes usually perform the function of transcription factor, regulator or tumor suppressors. Therefore, any mutation in their sequence leads to serious consequences such as leukemic blood cancer. Genetic heritability also contributes in increased risks of leukemia. However, researches are still under process to pin point the actual and major reason behind the genetic mutations that result in leukemia.

Diagnosis tests

There are some common tests which doctors use for leukemia diagnosis:

1. Full blood count

A full blood count (FBC) test measures the number of each type of cell in the blood. These include the RBC’s, WBC’s and platelets. Doctors may suggest this test as part of a routine check-up.

If the full blood count shows possibility of leukemia, the doctors may perform more tests. In case a person have leukemia, he/she need a regular FBCs to monitor the condition.

To perform the test, a blood film is taken from a sample of your blood. This is used for full blood count or person. Obviously, the blood count is more than the normal range due to abnormal and rapid growth of cancerous cell. The cells may be high in count but are abnormally developed and die soon.

2. Bone marrow aspirate and trephine

Sometimes the doctors perform analysis of bone marrow sample to check any possible issue in bone marrow in case the person has leukemia. This test provides information about the structure of the bone marrow, the number of cell and their distribution in marrow.

3. Immunophenotyping

Immunophenotyping (other names: immunophenotype analysis or flow cytometry) is performed for the purpose of looking at the pattern of cellular proteins.

To perform the test, the doctors perform bone marrow biopsy or blood tests. Later in laboratory procedure, a combination of the blood sample and particular antibodies is developed. The cells of immune system, secret various antibody molecules, to fight against infection. Similarly, there are certain antigens located on the surface of cancerous cells. Antigens are proteins whose presence characterizes the cancerous cells. The antibiotics actually identifies and binds to cancerous cells due to these antigens. The blood sample, when passes through an automated device, plots a graph on screen. The data interpretation of this graph represents the blood cells count and the number of abnormal cells is estimated.

The test is highly sensitive that even if there is a small count of abnormal cells in the sample.

4. Cytogenetic testing

Cytogenetic is the study of chromosomal structure and number. This involves the detailed analysis of structure and function of chromosomal structure. Just like all other types of cancer, leukemic blood cancer also has altered gene/chromosomes structure. Therefore, cytogenetic is useful as a diagnostic tool for leukemia. Other terms used for cytogenetic are karyotyping, FISH testing, molecular testing, and genetic testing.

5. Staging

Unlike the other types of cancer such as lung cancer or breast cancer, staging of leukemia is not possible. This is because blood cell circulates within the whole body by blood stream. When doctors perform diagnosis, they mainly identify the affected areas such as boon marrow.

6. Various Tomography scanning techniques

  • Computer Tomography (CT scan)

A CT scan is similar to X-ray. This is not a routine test for leukemia. However, doctors perform this test for specific conditions such as to check swollen liver and spleen

  • Magnetic Resonance Imaging (MRI)

This test shows up soft tissues (non-bony parts) and uses radio waves instead of X-rays. Similar to CT scan, MRI is not a routinely test for leukemia but only under certain conditions.

  • Position Emission Tomography (PET Scan)

Similar to an MRI, but the person is injected with a radioactive sugar. The levels of radiation used are very small and thus not harmful for the body. This test diagnoses the swollen lymph nodes. Doctors also use this to compare results after treatment.

7. Ultrasound scanning

This technique measures the size of your spleen, which is often enlarged if you have lymphoma. Moreover, it also helps to check swelling in lymph nodes during biopsy.

Treatment strategies

Treatment of blood cancer depends on the type of cancer and how much it has spread to body. As compared to other types of localized tumor, leukemia treatment is difficult due to its spreading to blood stream. Some of the treatment strategies are:

1. Chemotherapy

Chemotherapy applies anticancer drugs that kill the cancerous cells. These drugs basically interfere with growth of cancerous cells and inhibit their division and spread. For instance, busulfan, bosutinib and cytarabine and many more. Sometimes combined drug therapy is performed along with radiation therapy or other. One of the harmful aspects of chemotherapy is that these drugs may kill normal cells of body.

2. Radiation therapy

High energy radiations are directed for the purpose of killing cancerous cells. sometimes, radiation therapy is performed before the stem cell transplant.

3. Targeted drug therapy

This treatment strategy, target the specific antigens and surface proteins of cancerous cells. Thus, it kills only targeted cancerous cells. For instance, the drug imatinib (Gleevec) inhibits the protein synthesis in cancerous cell of chronic myeloid leukemia.

4. Stem cell transplant

Stem cells are undifferentiated cells of normal human body. These cells have the potential to develop into particular type of cell which the body requires. For instance, the stem cells of bone marrow and blood circulation and blood of umbilical cord. This is somewhat similar to bone marrow transplant. This treatment strategy replaces the damaged and cancerous bone marrow with the normal stem cells. a high infusion of blood cell helps the body to rebuild its normal healthy bone marrow that produces normal white blood cell. Thus, this will cure the leukemic cancer. Stem cell technology is recent development in the field of research and medicine. Have a detailed insight of this technique in our next article.

Bottom line

Leukemic blood cancer mainly affects the white blood cells. The cancer spread rapidly due to blood circulation. There are some diagnostic tests for its detection and treatment strategies that depend on type and severity of cancer.