Why Leukemia Happens: Could It Run in Your Family?

You may think that leukemia, which is cancer of the blood, develops randomly. But certain circumstances can increase your risk. And recent research identifies a new class of genetic mutations that may drive risk later in life.

Leukemia comes in many forms. It develops in children and adults, mostly older adults and men. It accounts for more than 3.6 percent of new cancer diagnoses. In most cases, doctors can’t pinpoint a cause.

Much research is currently ongoing to discover if there are biological processes and interactions that may lead to leukemia, says oncologist Sudipto Mukherjee, MD, MPH.

“There has been an explosion in research into trying to find out how certain changes in DNA can cause normal bone marrow cells to become leukemia cells,” Dr. Mukherjee says. “We are finding out more answers as we collect better, more systematic patient histories.”

What factors can increase your leukemia risk?

The more information doctors and researchers gather, the better they can identify why leukemia develops. Dr. Mukherjee lists four known environmental causes that can increase your risk:

1. Having a previous cancer treatment — Radiation or chemotherapy treatment for other cancers, such as those in the breast or lymphoma, increases your chances of developing leukemia. The toxic treatment compounds in your body, making a second cancer more likely, Dr. Mukherjee says.
2. Radiation exposure at work or in the environment — Several studies show an increase in certain types of leukemia among groups exposed to radiation over time, he says. For example, higher rates of leukemia have been reported in nuclear power plant workers, atomic bomb survivors and following exposure to medical imaging such as diagnostic CT scans in certain situations.
3. Contact with chemicals — Exposure to some chemicals, such as benzene, can increase your risk. Manufacturers use benzene in gasoline and throughout the chemical industry. There is a strong link between benzene and leukemia, as well as other blood cancers, says the American Cancer Society.
4. Smoking — Doctors usually link smoking with lung and oral cancers. However, the cancer-causing substances found in tobacco can enter the bloodstream. Tobacco-associated toxic chemicals can increase the risk of leukemia, Dr. Mukherjee says.

The family connection

Can leukemia run in your family? Yes, Dr. Mukherjee says, but it’s extremely rare. To date, researchers have identified few families with an inheritable form of leukemia, he says.

There are some genetic mutations, though, that can increase your leukemia risk. They include:

• CEBPA: This mutation causes low white blood cell count, increasing the likelihood you’ll develop infections. An associated low red blood cell count causes weakness and fatigue.
• DDX41: A mutation in this gene disrupts its ability to suppress tumors. Individuals with this defect are at greater risk for acute myeloid leukemia.
• RUNX1: This defect also causes low platelet counts, a symptom associated with leukemia.

Down syndrome and rare genetic conditions that increase the likelihood of leukemia include Fanconi’s anemia, Bloom syndrome, Diamond-Blackfan anemia, Shwachman-Diamond syndrome and Li-Fraumeni among others. If you or a relative has any of these conditions, your doctor may suggest meeting with the rest of your family.

Genetic counseling for families

If your doctor suspects that there is a genetic link to leukemia in your family, it’s a good idea to follow up on that possibility. The more you know, the better you and your doctor can monitor the situation for you and your relatives.

“It’s exceedingly rare for leukemia to run in families,” Dr. Mukherjee says. “But, if we know someone has a genetic defect, we can send them and their family members to get genetic counseling and the best treatment options.”