Causes and Risk Factors for Acute Myeloid Leukemia
Acute myeloid leukemia (AML) is an aggressive blood cancer that originates in the bone marrow, where abnormal myeloid cells multiply uncontrollably and interfere with normal blood cell production. Understanding the causes and risk factors for acute myeloid leukemia is essential for early detection, informed decision-making, and targeted prevention strategies.
Key Takeaways
- AML develops when genetic mutations disrupt normal myeloid cell development in the bone marrow.
- Chromosomal abnormalities, including translocations and deletions, are among the most significant genetic factors linked to AML.
- Exposure to ionizing radiation, benzene, and certain chemotherapy agents are established risk factors for AML.
- Age, sex, and pre-existing blood disorders are established demographic and clinical risk factors.
- Most AML cases arise without a single identifiable cause, reflecting a combination of genetic and environmental factors over time.
What Causes Acute Myeloid Leukemia (AML)?
AML arises when immature myeloid cells in the bone marrow acquire genetic changes that disrupt normal differentiation and proliferation. These abnormal cells, known as blasts, never finish maturing into working red cells, white cells, or platelets, and instead multiply quickly, taking over the space in the bone marrow that healthy cells need. Because this happens fast, the disease is classified as “acute.”
At its core, AML is a disease of DNA damage. Mutations can occur spontaneously, or they can be triggered by external exposures or, less often, an inherited predisposition. Genes such as FLT3, NPM1, CEBPA, and IDH1/IDH2 are among those most frequently altered in AML, and testing for these changes is a routine part of guiding treatment and estimating prognosis.
In many patients, no single definitive cause can be identified. AML typically results from an accumulation of multiple genetic changes over time rather than one isolated trigger, which makes the disease difficult to predict or prevent in any individual case.
Genetic and Chromosomal Factors Linked to AML
Genetic factors linked to acute myeloid leukemia represent one of the most thoroughly studied areas of AML research. Chromosomal abnormalities—structural changes in the DNA of myeloid cells—are found in approximately half of adult AML cases and carry significant prognostic value. These abnormalities include translocations, inversions, and deletions that alter gene expression and disrupt normal cell cycle regulation.
Among the most well-characterized chromosomal changes is the translocation between chromosomes 8 and 21, written as t(8;21), which fuses the RUNX1 and RUNX1T1 genes. Similarly, inversion of chromosome 16—inv(16)—disrupts the CBFB gene. Both alterations are generally associated with a more favorable prognosis. In contrast, a complex karyotype (three or more chromosomal abnormalities) or a monosomal karyotype tend to predict poorer treatment outcomes.
Point mutations in individual genes also drive AML development. FLT3 and NPM1 are among the most commonly altered genes in adult AML and are routinely tested because they carry treatment and prognostic implications—for example, an NPM1 change generally signals a more favorable outlook when it occurs without an accompanying FLT3 mutation. A small number of AML cases arise in people with an inherited genetic predisposition, though most AML remains sporadic, occurring without a known inherited cause.
Certain inherited syndromes are associated with a higher lifetime risk of AML, including Down syndrome, Fanconi anemia, Shwachman-Diamond syndrome, and Diamond-Blackfan anemia. Infants with Down syndrome who develop transient abnormal myelopoiesis—a bone marrow condition that usually resolves on its own within a few months—face a meaningfully increased chance of developing AML before age 3.
Environmental and Lifestyle Causes and Risk Factors for Acute Myeloid Leukemia
Environmental causes of acute myeloid leukemia have been identified through decades of epidemiological research and occupational health studies. Exposure to ionizing radiation is an established risk factor, whether from environmental sources such as nuclear radiation or from radiation therapy previously given for another cancer.
Benzene, an industrial chemical found in cigarette smoke, gasoline, and certain manufacturing processes, is a recognized cause of AML. Occupational or long-term exposure to benzene has been linked to AML development, and limiting contact with it—along with following workplace safety protocols—is one of the few modifiable ways to lower risk.
Prior treatment with certain chemotherapy drugs, particularly alkylating agents (such as cyclophosphamide and melphalan) and topoisomerase II inhibitors (such as etoposide), can lead to therapy-related AML, also called secondary AML. This form of the disease typically emerges five to six years after the original chemotherapy, though the reported time to onset varies widely—from under a year to more than a decade—and it often carries a less favorable prognosis than AML that arises without a prior cancer treatment.
Cigarette smoking is another well-established, modifiable risk factor for AML. Tobacco smoke contains benzene and other substances that enter the bloodstream and reach the bone marrow, and quitting smoking is linked to a lower risk of the disease.
| Risk Factor | Type | Evidence Level |
|---|---|---|
| Ionizing radiation exposure | Environmental | Strong (clinical and occupational data) |
| Benzene exposure | Environmental / Occupational | Strong (established exposure data) |
| Prior chemotherapy (alkylating agents, topoisomerase II inhibitors) | Medical / Treatment-related | Strong (clinical data) |
| Cigarette smoking | Lifestyle | Established risk factor |
| Chromosomal abnormalities (e.g., t(8;21), inv(16)) | Genetic | Strong (cytogenetic data) |
| Inherited syndromes (e.g., Down syndrome, Fanconi anemia) | Genetic / Hereditary | Strong (clinical and genetic data) |
| Pre-existing blood disorders (MDS, MPN) | Clinical | Strong (hematological evidence) |
Who Is Most at Risk for Developing Acute Myeloid Leukemia?
Several demographic and clinical characteristics define population groups with the highest AML burden. Age is the most significant non-modifiable risk factor: according to SEER data from the National Cancer Institute, the median age at diagnosis is around 70, and more than 6 in 10 new AML cases are diagnosed in people age 65 or older.
SEER data show that sex plays a role as well: AML occurs at an age-adjusted rate of about 5.2 cases per 100,000 men compared with 3.7 per 100,000 women each year, though the reasons for this difference are not fully understood. By race and ethnicity, non-Hispanic White populations show the highest incidence rates, while Hispanic and Asian/Pacific Islander populations show among the lowest; disparities in access to diagnostic care may also contribute to differences in reported rates. These are population-level averages, not an estimate of any one person’s individual risk.
Individuals with pre-existing hematologic conditions carry a substantially elevated risk. Myelodysplastic syndrome (MDS) and myeloproliferative neoplasms (MPN)—including polycythemia vera and essential thrombocythemia—can progress to AML over time. This transformation, sometimes called secondary or evolved AML, tends to be harder to treat than AML that arises without a prior blood disorder. Regular monitoring of patients with these conditions is therefore clinically important.
Most AML cases are sporadic, meaning they occur in people without a notable family history. When several relatives have had leukemia or a related blood cancer, a doctor may suggest checking for an inherited predisposition syndrome. For most people, the combination of advancing age, cumulative environmental exposures, and the gradual buildup of genetic changes over a lifetime is the most common scenario underlying AML.
Frequently Asked Questions
Is acute myeloid leukemia hereditary?
Most AML cases are not hereditary and arise from genetic changes that happen over a person’s lifetime rather than from changes inherited at birth. A small subset of cases occur in people with inherited syndromes, such as Down syndrome, Fanconi anemia, or Shwachman-Diamond syndrome, that raise lifetime AML risk. A genetics specialist can be helpful to consult when several relatives have had leukemia or when a predisposition syndrome runs in the family.
Can lifestyle changes reduce the risk of developing AML?
While AML cannot be fully prevented, a few modifiable factors can lower risk. Avoiding tobacco smoke limits exposure to benzene and other substances linked to AML, and limiting contact with industrial chemicals or following workplace safety protocols for radiation and chemical exposure can also help. These steps lower overall risk but cannot guarantee prevention, particularly for people with a strong genetic predisposition.
How does prior cancer treatment increase AML risk?
Certain chemotherapy drugs, especially alkylating agents and topoisomerase II inhibitors, can damage DNA in bone marrow cells and trigger the changes that lead to therapy-related AML. This form of AML typically appears five to six years after the original treatment, though the time to onset can range from under a year to more than a decade. Radiation therapy can carry a similar risk. Because of this, doctors weigh these long-term risks carefully when planning treatment for other cancers, especially in younger patients with longer life expectancies.
Sources
