Leukemia is a type of cancer that begins in the blood-forming tissues of the body, such as the bone marrow and lymphatic system. Unlike other forms of cancer that affect a specific organ, leukemia disrupts the production and function of blood cells, particularly white blood cells. While the exact causes of leukemia remain unclear in many cases, scientific research has identified a range of potential risk factors and triggers that contribute to its development.

Unlike some cancers that are clearly linked to lifestyle choices or environmental exposure, the causes of leukemia are more complex and not yet fully understood. In many cases, people diagnosed with leukemia have no clear risk factors. However, scientific research has identified a number of possible triggers and contributing factors, ranging from genetic mutations and inherited disorders to exposure to radiation, chemicals like benzene, certain viral infections, and previous cancer treatments.

What Is Leukemia?

Leukemia is a cancer of the blood and bone marrow. It typically involves an abnormal increase in white blood cells, which do not function properly. These dysfunctional cells crowd out healthy blood cells, making it harder for the body to fight infections, control bleeding, and transport oxygen. Leukemia is classified into four main types :-

Acute lymphoblastic leukemia (ALL)
Acute myeloid leukemia (AML)
Chronic lymphocytic leukemia (CLL)
Chronic myeloid leukemia (CML)

Each type behaves differently and may have different risk factors, though some underlying causes may overlap.

Causes of Leukemia

Genetic Mutations and Leukemia :- One of the leading causes of leukemia is genetic mutation. In many cases, changes in the DNA of blood cells lead to uncontrolled cell growth. These mutations can affect oncogenes (which promote cell division) or tumor suppressor genes (which normally slow cell division or cause cells to die at the right time).
Sometimes, these mutations are inherited, but in most leukemia cases, they are acquired during a person’s lifetime. Exposure to harmful chemicals, radiation, or certain viral infections may contribute to these changes at the cellular level. While scientists do not always understand why these mutations occur, it is clear that they are a central feature in the development of leukemia.
Exposure to Radiation :- Radiation exposure is a well-documented risk factor for leukemia. High doses of ionizing radiation such as those from atomic bomb explosions or radiation therapy for other cancers have been strongly linked to the onset of certain types of leukemia, particularly acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL).
Even lower-level exposure to radiation over a long period, such as from occupational hazards in medical or nuclear industries, may pose an increased risk. However, everyday exposure from X-rays or natural sources is considered minimal and typically not linked to leukemia.
Chemical Exposure and Environmental Factors :- Prolonged exposure to certain chemicals can also increase the likelihood of developing leukemia. Benzene is one of the most well known chemicals associated with leukemia. This industrial solvent is found in products like gasoline and is used in the manufacturing of plastics, rubber, and dyes.
People who work in industries involving benzene or who are exposed to it regularly have a higher risk of developing AML. Other environmental toxins and pollutants may also play a role, but benzene remains the most clearly established chemical link to leukemia.
Inherited Genetic Disorders :- Some inherited conditions can increase the risk of leukemia. These include :-
- Down syndrome :- Children with Down syndrome are more prone to developing both ALL and AML.
- Li-Fraumeni syndrome :- This rare genetic disorder increases the risk of multiple cancers, including leukemia.
- Fanconi anemia and Bloom syndrome are other inherited conditions that impair the body’s ability to repair DNA, leading to a higher chance of leukemia.
While these disorders are rare, they highlight the role that genetics can play in making someone more susceptible to blood cancers.
Immune System Disorders :- Individuals with weakened immune systems are at a higher risk of developing leukemia. This includes people with autoimmune diseases, those undergoing long-term immunosuppressive therapy (e.g., after an organ transplant), and individuals with HIV/AIDS. A compromised immune system is less able to regulate abnormal cell growth, allowing leukemia cells to multiply unchecked.
Previous Cancer Treatments :- Ironically, cancer treatments themselves can sometimes lead to leukemia. Chemotherapy and radiation therapy, especially when given in high doses or over long durations, can damage bone marrow and alter DNA in blood forming cells. This secondary leukemia often appears years after the initial treatment and is usually in the form of AML.
Drugs such as alkylating agents and topoisomerase inhibitors are known to increase this risk, particularly when used in combination.
Viral Infections :- Certain viral infections have been linked to an increased risk of leukemia. One of the most studied is the human T-cell leukemia virus type 1 (HTLV-1), which is associated with adult T-cell leukemia/lymphoma. Additionally, the Epstein-Barr virus (EBV) and HIV can also affect the immune system and may play a role in blood cancer development, although the mechanisms are not yet fully understood.
Smoking and Lifestyle Factors :- While leukemia is not as strongly associated with lifestyle choices as other cancers like lung or liver cancer, smoking has been shown to increase the risk of developing AML. Tobacco smoke contains benzene and other harmful chemicals that may directly affect blood cells and bone marrow. Additionally, a sedentary lifestyle, poor diet, and chronic exposure to environmental toxins may also contribute indirectly to leukemia risk by weakening the immune system and cellular health.
Age and Gender :- Leukemia can occur at any age, but certain types are more common in specific age groups. For instance, ALL is more common in children, whereas CLL typically affects older adults. AML and CML also tend to occur more frequently in people over 60. Men are slightly more likely than women to develop most types of leukemia, though the reasons are not entirely understood.
Family History of Leukemia :- Having a first degree relative with leukemia slightly increases your risk of developing the disease. While most leukemia cases are not hereditary, the presence of leukemia in close family members suggests a possible shared genetic predisposition or environmental exposure. However, this risk is relatively small compared to other factors such as chemical exposure or prior cancer treatments.

Conclusion

Leukemia is a complex disease with no single known cause. Its development typically results from a combination of genetic, environmental, and lifestyle factors. While some risk factors like genetic predisposition or age are unavoidable, others, such as smoking or chemical exposure, can be minimized with conscious choices and awareness.