Non-Hodgkin lymphoma (NHL) is a type of cancer that originates in lymphocytes, which are a type of white blood cell forming part of the body’s immune system. These cells are found in the lymphatic system, including lymph nodes, the spleen, and bone marrow. When lymphocytes develop abnormally and grow uncontrollably, they can form tumors, leading to NHL. Many individuals wonder if this condition is inherited, a question that will be explored in this article.
Understanding Non-Hodgkin Lymphoma and its Genetic Basis
Non-Hodgkin lymphoma is not considered an inherited disease. While NHL involves genetic changes in the DNA of lymphocytes, these alterations are acquired during a person’s lifetime. These acquired mutations cannot be inherited from parents. They occur as cells divide and grow, sometimes due to environmental factors or by chance, and accumulate over time.
These acquired genetic changes lead to the uncontrolled growth and division of lymphocytes, a hallmark of cancer development. For instance, in follicular lymphoma, cells exhibit a translocation between chromosomes 14 and 18, activating the BCL-2 oncogene. This alteration prevents cells from undergoing their natural death cycle, contributing to the proliferation of abnormal lymphocytes. Scientists have identified several gene changes linked to various NHL subtypes, but the exact mechanisms by which these acquired changes lead to NHL are still being investigated.
Common Risk Factors for Non-Hodgkin Lymphoma
Since NHL is not an inherited condition, its development is linked to acquired risk factors. A weakened immune system increases NHL risk. This can result from autoimmune diseases, where the body’s immune system mistakenly attacks its own tissues, or from medical treatments like immunosuppressant drugs used after organ transplants. For example, individuals with conditions such as rheumatoid arthritis, lupus, or Sjögren’s syndrome have an elevated risk.
Certain infections are also recognized risk factors for NHL. The Epstein-Barr virus (EBV), which causes mononucleosis, is associated with an increased risk of certain NHL types. Infections with Helicobacter pylori bacteria, often linked to stomach ulcers, can increase the risk of MALT lymphoma. Hepatitis C virus and human T-cell lymphotropic virus (HTLV-1) have also been identified as contributing factors to certain lymphomas.
Exposure to chemicals, such as pesticides and herbicides, as well as radiation exposure, are under investigation for their links to NHL. The risk of developing NHL also increases with age, with over 35% of diagnoses occurring in individuals aged 75 and over.
The Role of Family History in Non-Hodgkin Lymphoma
While NHL is not inherited, having a close family member, such as a parent, sibling, or child, with the condition may slightly increase risk. This increased risk is small and does not signify a direct inheritance of the disease. First-degree relatives of NHL patients have an approximately 1.7-fold higher risk of developing NHL. This familial aggregation could be attributed to shared environmental exposures, similar lifestyle choices, or a complex interplay of subtle genetic predispositions that are not yet fully understood.
This increase in risk does not mean that NHL is passed directly from parent to child. Most individuals with a family history of NHL will not develop the disease. The exact reasons behind this familial tendency are still being researched, with scientists exploring whether it involves multiple small genetic changes that collectively contribute to a predisposition, rather than a single inherited gene directly causing the lymphoma.
Rare Genetic Syndromes and Non-Hodgkin Lymphoma Risk
In rare instances, certain inherited genetic conditions can raise risk of developing Non-Hodgkin Lymphoma. These syndromes are characterized by impaired immune system function, making individuals more vulnerable to various infections and cancers, including NHL. Examples include ataxia-telangiectasia, a disorder affecting the nervous and immune systems, and Wiskott-Aldrich syndrome, a rare genetic disease that impacts specialized immune cells.
Common variable immunodeficiency (CVID) is another inherited condition that can increase NHL risk due to a compromised immune system. While these syndromes present a higher predisposition to NHL, they are rare and account for a small fraction of all NHL cases diagnosed. For the majority of individuals who develop NHL, these inherited genetic syndromes are not a contributing factor.