DNA Tests for Leukemia
The risk factors for Leukemia are numerous, and new genetic testing is being developed every day. Here at YourDNA, we are keeping up with the latest facts so we can keep you, our readers informed of the possible life-altering ramifications of this technology.
Leukemia is a type of cancer that affects your blood cells. It starts with a mutation that continues to grow until the mutated cells outnumber the normal, healthy ones.
While the disease is caused by a blood cell mutation and is considered a genetic disease, it’s not common for the disease to be hereditary.
DNA testing for leukemia isn’t typically completed to determine one’s risk factor for most leukemia types because the cell mutation isn’t often hereditary, but there is a DNA test available that could determine your risk of developing chronic lymphocytic leukemia (CLL).
Also, DNA testing can help your doctor determine your risk level for relapse after leukemia is treated in some cases.
What Are the Different Types of Leukemia?
Leukemia is a type of cancer that begins in the blood-forming cells of your bone marrow.
There are several versions of leukemia, but the four most prevalent ones are — acute myeloid leukemia, acute lymphocytic leukemia, chronic myeloid leukemia, and chronic lymphocytic leukemia.
In chronic types of leukemia, your blood cells start to mature, but they don’t mature completely. This means they don’t fight infection as well as normal, healthy white blood cells.
Because the cells don’t fully mature, they also live longer than normal, healthy blood cells, eventually crowding them out. Chronic types of leukemia take longer to diagnose and cure and they are also harder to cure.
With acute leukemia, the abnormal cells mature and reproduce, but they don’t mature the way they should. Typically, acute leukemias develop seemingly out of nowhere and progress quickly, but fortunately, they are easier to cure than chronic types and DNA testing can help determine your risk of relapse after treatment.
What Are the Genetic and Environmental Risk Factors for Leukemia?
There are several different types of leukemia, and scientists believe that they are caused by a mutation in your blood cell’s DNA.
The mutation changes the way the blood cells in your bone marrow reproduce, and eventually, the altered CEBPA genes outnumber the good, healthy blood cells in your body.
While the mutation is genetic, it’s not necessarily hereditary. This means that even though leukemia is caused by a mutation in your body cell’s DNA, altered CEBPA genes aren’t something typically passed down in families from generation to generation.
Instead, altered CEBPA genes are usually an acquired gene mutation.
You can be genetically disposed to leukemia, but usually, the mutation that causes the disease comes from environmental factors — some of which you can control and some of which you can’t. Some of the environmental factors that increase your risk of developing leukemia include:
- Cigarette smoking
- Frequent exposure to benzene, a chemical commonly found in gasoline, oil refineries, shoe manufacturing plants, and chemical plants
- Frequent exposure to formaldehyde, normally found in household materials and products
- Exposure to Agent Orange, a chemical used during the Vietnam War
- Previous cancer treatments that contain specific chemotherapy drugs such as alkylating agents, platinum agents, and topoisomerase II inhibitors
- Previously undergoing both chemotherapy and radiation treatments
- Viral infections with the human T-cell lymphoma/leukemia virus-1, which is most commonly found in the Caribbean and Japan
In addition to the factors listed above, your age, gender, and race may also increase your chances of getting leukemia. Studies show that risk increases with age and men are more likely to get the disease than women.
Research has also shown that some groups of people are more likely to develop specific types of leukemia. For example, people of European descent are more likely to develop CLL than other races of people.
And Asian people have very little risk of developing leukemia — which scientists believe is due to having different genetic dispositions.
Some blood disorders can increase your risk of developing acute lymphocytic leukemia (ALL), including:
- Polycythemia vera
- Primary thrombocythemia
While your family’s medical history doesn’t determine whether you have a higher risk of developing the majority of leukemia types, CLL is the exception. CLL does occur more often when people have a close family member with the disease.
This means if your mother, father, or one of your siblings has leukemia, you’re considered to have a higher risk of developing CLL. Lastly, if you’re an identical twin whose twin developed acute lymphocytic leukemia before he or she was one year old, you have an increased risk of developing ALL yourself.
Are There DNA Tests for Predicting the Risk of Leukemia?
While DNA testing can’t predict whether or not a person will get leukemia, it can help predict the prognosis of CLL.
Genetic testing can detect abnormalities in four out of five CLL patients. The testing tells doctors the exact type of abnormality present in a person’s blood cells, which allows them to customize treatment plans for patients, thus improving the person’s overall prognosis.
In some cases, CLL is a slow-moving disease — some patients can go years without detection and treatment. However, there are also more aggressive forms of CLL, and these need to be treated as soon as possible.
By completing a DNA test after you’ve been diagnosed with CLL, your doctor can determine whether the type of CLL you have is one that progresses slowly or quickly. Then, he or she can ensure you receive the proper treatment, increasing your chance of survival.
Are There DNA Tests for Predicting the Risk of Leukemia Relapse?
In the fall of 2018, scientists in Canada and Korea developed the first genetic test that predicts the risk of leukemia relapse.
However, the DNA-based test doesn’t determine the likelihood of relapse for all types of leukemia. It’s only used to predict relapse for people who have acute myeloid leukemia (AML) or ALL.
The test can be taken three weeks after chemotherapy treatment and a bone marrow transplant has been completed. It’s designed to detect mutations in your bone marrow cells in small amounts.
This is especially important for people who have AML because this type of leukemia starts suddenly, progresses quickly, and is the most common type of leukemia seen in adults.
Typically, chemotherapy wipes out the diseased bone marrow, which is then replaced with healthy bone marrow from a matching donor. Most people go into remission immediately after treatment, but approximately one-third of people in remission from AML relapse within three to six months.
Because the DNA test can detect problem cells in small traces, the test allows doctors to complete intermediate treatments with patients who are at a high risk of relapse earlier, which improves the patient’s outcome in the long run.
What DNA Tests Are Available for Leukemia Risk?
DNA testing isn’t normally used to estimate someone’s risk of developing leukemia because most cases aren’t hereditary.
However, if your doctor suspects that symptoms you have could be caused by leukemia, he or she may order one of several chromosome tests that examine your DNA to determine if there are abnormalities in your blood cells.
Human cells contain 23 pairs of chromosomes — long strands of DNA. However, when you have ALL, and other types of leukemia, the chromosomes in your blood cells are altered slightly.
In people with ALL, two chromosomes swap some of their DNA — this is called translocation. Most commonly, when translocation occurs, the result is a shortened number 22 chromosome, which is called the Philadelphia chromosome.
It’s important for DNA testing to look for this marker because one in four adults with ALL has a shorter-than-normal Philadelphia chromosome.
Some of the most common DNA tests completed when people are suspected to have leukemia include:
- Cytogenetics testing: When a cytogenetic test is performed, blood cells are placed in lab dishes until they begin to multiply on their own. Once this happens, in approximately two to three weeks, the cells are closely examined under a microscope for any changes or mutations. In some cases, changes in cells can’t be detected under a microscope, which is why further testing might be needed.
- Fluorescent in situ hybridization (FISH) testing: The good thing about FISH testing is that it can be used on either blood or bone marrow samples. It’s able to detect most mutations that are visible under a microscope during regular cytogenetics testing, as well as some mutations that are too small to be seen under a microscope. Because the cells don’t need to divide in order to complete FISH testing, you can typically get results from this test back within two to three days. However, the testing doesn’t look at your chromosomes overall. Because of this, it’s typically used to look for specific changes in cells that occur with the type of leukemia you have.
- Polymerase chain reaction (PCR) testing: This is a particularly sensitive DNA test that has the ability to detect changes in cells even when very few leukemia cells are present. However, like the FISH test, PCR testing doesn’t examine your chromosomes overall. Instead, it tests your blood cells for specific changes and mutations.
Are There At-Home DNA Tests for Leukemia?
Unfortunately, there aren’t any at-home DNA tests that you can use to predict your risk of leukemia.
This is because DNA tests aren’t used to predict one’s leukemia risk at all. There are several types of leukemia, but only CLL has the possibility of being hereditary.
So in most cases, completing a DNA test won’t tell you whether you’re at risk or not. However, DNA testing is used in the treatment of CLL and to determine whether someone with ALL or AML will relapse, but there aren’t at-home versions of these DNA tests either.
Where Can I Get My DNA Tested for Leukemia?
Typically, leukemia is a disease that’s first detected when your doctor tests your blood during your annual physical exam.
The blood taken during your exam is tested for various things, including to measure the number of red blood cells, white blood cells, and platelets in your blood. They also look for other chemicals and biomarkers in your blood that could indicate whether or not you have cancer.
If your doctor is concerned about the results of your bloodwork, he or she usually orders a blood smear. To complete this test, the lab tech smears a small amount of your blood on a glass slide and examines it under a microscope.
This lets the lab tech see if your red blood cells, white blood cells, and platelets are normal in both appearance and number.
If the blood smear indicates you have CLL, your doctor may order DNA testing to determine the best course of treatment. If you have AML or ALL, your doctor probably won’t order DNA testing until you’ve completed treatment to determine your risk of relapse.
For other leukemia types, DNA testing isn’t needed because it’s not typically a disease that’s hereditary.
If a Person Tested Positive, Is There a Way to Prevent Progression Towards Leukemia?
As we’ve said, DNA testing isn’t completed to determine whether or not you are likely to get leukemia, because most forms of the disease aren’t hereditary.
However, if you have a close family member — mother, father, or sibling — with CLL, you do have a greater chance of developing that form of leukemia yourself. So if that’s the case, you should consider eliminating as many of the high-risk environmental factors as possible.
For example, it’s a good idea to quit smoking and limit any exposure to benzene you may have. While this won’t guarantee you won’t develop leukemia, it can help lower your overall risk, even if you have some mutated blood cells in your body.
If you test positive for leukemia, it’s important to get treatment as soon as possible. Further testing, which in some cases includes DNA testing, helps your doctor determine the type of leukemia you have and how aggressive it is, which in turn makes it easier for your doctor to determine the best treatment options.
Your oncologist will discuss treatment options with you, including the prognosis for each form of treatment.
If you have another type of cancer and you’re worried about developing leukemia in the future, you should discuss this with your oncologist.
Keep in mind, even though chemotherapy and radiation treatments increase your risk of developing leukemia, it might be a risk that’s necessary when battling other, more aggressive, forms of cancer.
Are There Genetic Predispositions to Childhood Leukemia?
Leukemia is one of the most common childhood cancers. In fact, it accounts for 31 percent of cancers in children younger than age 15 — and 25 percent of cancers in children younger than age 20.
However, genetics doesn’t play a huge role in the development of childhood leukemia.
In most cases, childhood leukemia develops because of a random blood cell mutation. Because of this randomness, there’s no way to determine whether or not one of your children will develop leukemia.
However, there are a few syndromes that are caused by mutations in the “germline” that show up in every cell of the body. If your child has one of these syndromes, it creates a predisposition for developing various cancer types, including leukemia.
Only about 10 percent of children with leukemia have a cancer predisposition gene. So testing isn’t something that’s completed automatically for every child.
However, if you or another close blood relative is diagnosed with a leukemia predisposing syndrome, chances are, your pediatrician will order blood tests to see if any abnormal cells are present, and it’s something that may be watched closely as your child grows.
Basically, genetic testing for leukemia is typically completed if the child or either of the child’s parents has a syndrome that puts the child at a higher risk for developing leukemia.
Syndromes that put children at a higher risk for leukemia include:
- Li-Fraumeni syndrome
- Neurofibromatosis 1
- Noonan syndrome
- Fanconi anemia
- Shwachman-Diamond syndrome
- Wiskott-Aldrich syndrome
- Bloom syndrome
Children with Down syndrome also have a higher risk of developing AML and ALL than other children. This syndrome has also been linked to transient myeloproliferative disorder, which is similar to leukemia.
However, this disorder develops within the first month of a child’s life and usually goes away on its own.
What Other Scientific Advances Are Being Made for Diagnosing Leukemia-Predisposition?
Most scientific studies surrounding leukemia are focused on the treatment of the disease.
This is because most cases of leukemia develop randomly, so completing DNA testing won’t help you determine whether you have a higher risk of developing the disease or not.
Instead, scientists have recently proven that a combination of chemotherapy and immunotherapy has been effective in treating the disease. They have also developed a way to help new blood cells regenerate quicker after a bone marrow transplant.
This is extremely good news for people with leukemia because they often battle excess fatigue and are really vulnerable to infection while new blood cells regenerate.
Additionally, scientists recently confirmed that DNA testing has successfully been used to determine whether people with ALL or AML will relapse after treatment. This discovery should have a huge impact on people with ALL specifically because this type of leukemia gets aggressive quickly.
But because DNA testing can help determine whether or not the person may relapse after treatment, doctors can use prescription medication to treat people at high risk of relapse in hopes of keeping them in remission for as long as possible.
Can You Do Anything to Reduce Your Risk of Leukemia?
Like with other types of cancer, you can reduce the risk of developing leukemia by living by making healthy lifestyle choices.
One of the most effective ways to prevent leukemia is to quit smoking. When you smoke tobacco, it introduces various harmful chemicals into your body, which are carried through your bloodstream.
Exposing your blood cells to these chemicals can result in abnormal growth of new cells, which could eventually turn into leukemia.
It’s also important to maintain a healthy body weight. Studies have shown that being overweight could increase your risk of developing leukemia and other forms of cancer.
However, you can reduce your leukemia risk by maintaining a healthy weight through diet and exercise.
Additionally, if you want to lower your risk of developing leukemia you should also manage occupational and environmental exposures that increase your risk of leukemia.
This means if you work in a place that puts you in regular contact with chemicals like benzene or formaldehyde you should consider changing careers or switching to products that are benzene-and formaldehyde-free if possible.
Benzene is typically found in gasoline, vehicle exhaust, glue, paint, and cleaning products. Formaldehyde is often found in building materials and household products, including particle board, plywood, and fiberboard, as well as glues, permanent-press fabrics, and insulation.
Also, it’s important to limit the amount of unnecessary radiation you’re exposed to. This means if it isn’t absolutely necessary for medical purposes to expose yourself to radiation, you shouldn’t.