Is Leukemia Genetic?

Leukemia is a type of cancer that usually begins in the bone marrow and can cause an increase in the growth of abnormal white blood cells, severely impairing the immune system of the body. There are primarily four types of leukemia, including acute myeloid leukaemia, acute lymphoblastic leukaemia, chronic myeloid leukemia, and chronic lymphocytic leukaemia. It highly affects the age group of 41-60 years and is diagnosed by laboratory studies on a blood sample, a bone marrow biopsy, a chest X-ray, and/or a lumbar puncture.

Signs and Symptoms

The common signs and symptoms of leukemia include pain in the joints, swollen lymph nodes, unexplained fever, anemia, fatigue, weight loss, easily bruising or bleeding, seemingly unexplained weight loss, and lowered immunity. Treatment for the condition is highly variable and subjective. Generally, monitoring is considered for slow growing leukemia and chemotherapy/radiation/bone marrow or stem cell transplant for aggressively growing versions of leukemia. However, there is no known way to prevent leukemia. The prognosis of this type of cancer solely depends on the patient’s age, the extent to which the leukemia has spread in the body, and the type of leukemia that is diagnosed.

Risk Factors and the Definitions of Genetic and Hereditary

Although many risk factors for the condition have been identified, the genetic predisposition of leukemia is still not confirmed. Before we understand the genetic influence on leukemia, let us know what the terms genetic and hereditary actually mean.

What do the terms genetic and hereditary actually mean? Genetic and hereditary are oftentimes used interchangeably and are construed as synonymous. However, technically speaking, there are certain traits and features that would show or define the difference between genetic and hereditary. There are several human traits and/or diseases that can be attributed to genetics but that are not hereditary, or are shown to be hereditary without being genetic, although others would appear to be both hereditary and genetic.

The word genetic is defined as a feature or trait that directly or indirectly determines or associates a disease with the organism's genetic makeup, while the ability to pass on the same genetic trait from parents to offspring or from one generation to the next is called hereditary.

An example of a feature that often appears to be genetic but not hereditary is certain types of cancer or malignant growths. Primarily, cancer is considered to be a genetic disorder, as they arise from abnormal mutation of genes, which does not necessarily mean that it has been passed on from the previous generation, as it would be with a hereditary disorder. The mutation may be due to several environmental factors that the person has acquired through time. Keep in mind that initially cancer cells are dormant abnormal cells that can cause the person not to have any signs and symptoms of the disease unless certain carcinogenic agents trigger their activation.

The development of leukemia is mainly attributed to a combination of genetic factors, as well as some environmental factors, as its exact cause is still continuously being studied. In general, leukemia is the cancer of the blood or the bone marrow that is responsible for the production of blood cells. Mainly, it is an abnormal production of white blood cells, also called leukocytes. Studies believe that leukemia arises when there is an abnormal mutation in the blood cells’ DNA, as DNA dictates the cell function and its action, which influences other organ functions. The abnormalities will lead to a rapid growth and division of cells, which causes the number of abnormal cells to be much higher than the healthy cells, leading to the manifestation of leukemia signs and symptoms.

In a general sense, most of the reported cases of leukemia are not due to hereditary factors. Progressively, there are certain genetic conditions and mutations which can be passed along through genetic factors, and these can increase the chances of an offspring developing leukemia. There are many conditions, like Down syndrome, Li-Fraumeni syndrome, neurofibromatosis type 1, Noonan syndrome, and ataxia telangiectasia, that increase the risk of leukemia and other cancers. Due to chromosomal abnormalities, it has been observed that people with Down syndrome are at a higher risk of developing leukemia, as well as with other diseases that involve certain chromosomal anomalies. Some researchers have looked into the family history of people with leukemia and have found that having a genetic predisposition to leukemia puts their lineage at a higher risk of having the same disease.

Other possible causes that contribute to the development of leukemia that experts are keenly looking into are the exposure to benzene and some petrochemicals, artificial ionizing radiation, certain viruses such as human T-lymphotropic virus or HTLV-1, and human immunodeficiency virus or HIV, alkylating chemotherapy agents as part of a previous cancer treatment, and even hair dyes. In rare cases, maternal fetal transmission is also suspected to be a cause of leukemia. Cigarette smoking has been closely linked to the development of myelogenous leukemia. 

Classification of Leukemia

Leukemia is classified based on how fast the disease is progressing, as well as the involved blood cells. First, the two classifications of leukemia based on the progression are Acute Leukemia and Chronic Leukemia. Acute leukemia arises due to the increasing presence of immature blood cells that are unable to perform their normal cell function and that are rapidly multiplying; hence, the disease worsens within a short period of time and requires immediate treatment. On the other hand, with Chronic leukemia, the progression is much slower. The bone marrow produces more mature cells that are unable to perform their normal cell function for an extended period of time with early symptoms that seem unnoticeable and can go undetected or undiagnosed for a few years until much worse symptoms appear.

Second, the two types of classifications of leukemia based on the affected white blood cells are Lymphocytic Leukemia and Myelogenous Leukemia. Lymphocytic leukemia has a direct effect in the body’s immune system, as it involves the lymphoid cells or lymphocytes, which are another kind of white blood cell that forms the lymphatic tissue. While with Myelogenous leukemia, there is an abnormal production of myeloid cells, which are the type of cells responsible for the formation of certain kinds of white blood cells, red blood cells, and platelets.

Final Thoughts

Leukemia is considered to be mainly genetic and not necessarily hereditary. The genetic changes may be due to environmental factors.