What is follicular lymphoma, and how does genetics play a role?

The lymphatic system is vital to the human body’s immune system. It produces and transports lymph cells throughout the bloodstream and acts in the event of infections or other diseases [1]. 

It comprises an extensive network of lymphatic vessels branching through veins and arteries and lymph nodes throughout the body (tonsils, adenoids, spleen, and thymus). When follicular lymphoma occurs, it affects the lymphoid tissue, of which the entire system is composed of B and T lymphocytes [2]. 

But are follicular lymphoma and genetics related? 

What is a follicular lymphoma?

A follicular lymphoma is a type of cancer that appears in the leukocytes (white blood cells), lymphatic system, and bone marrow. It’s a subtype of non-Hodgkin’s lymphoma in which cells in the lymphoid tissues multiply uncontrollably, causing tumor growth that triggers cancer [2]. It’s the second most common type of lymphoma after Hodgkin’s lymphoma. [3]

In general, lymphocytes have a predictable life cycle: old lymphocytes die, and the body creates new ones to replace them. When follicular lymphoma occurs, the lymphocytes don’t die, and the body keeps making new ones. The excess lymphocytes accumulate in the lymph nodes and enlarge them.[4] They are slow-growing and mainly affect the lymph nodes.

Its growth is slow and particularly affects B lymphocytes. It mainly influences the lymph nodes, eventually spreading to the bone marrow or spleen. Most patients diagnosed with follicular lymphoma are over 50 years of age [5].

The lymphatic system is responsible for filtering blood, draining fluid from tissues back into the bloodstream, and fighting infection. Lymphoid tissue is found throughout the body, so that follicular lymphoma can begin almost anywhere [2].

Symptoms of follicular lymphoma

Symptoms of follicular lymphoma and signs to watch for are:

• Swollen lymph nodes in the neck, armpit, or groin area. The swollen lymph nodes may compress some vital organs, causing chronic coughing, breathing problems, or chest, abdominal or lumbar pain, depending on the organ affected.
• Fever. Intense night sweats.
• Weight loss (unintended).
• Tiredness due to anemia. 
• Infections. Due to the malfunctioning of the lymphatic system that protects against infections due to cancer, patients may suffer from recurrent infections or infections that become difficult to treat.

Although rare, some of the symptoms of follicular lymphoma are caused by decreased production of thrombocytes in the bone marrow, which can lead to bleeding, easy bruising, bleeding from the nose or gums, and the appearance of small red spots on the skin (usually on ankles and shins) [2].

Causes of follicular lymphoma

In many cases, it’s unknown what exactly causes follicular lymphoma, but different factors can influence its development.

Lifestyle, environmental factors, and previous medical conditions have been linked to follicular lymphoma, but their influence is not yet evident.

• Diet: a link has been identified between follicular lymphoma and the consumption of meat and milk, in addition to nitrates and nitrites found in cured meat, food preservatives, or some fruits.
• Alcohol: wine consumption increases the risk of follicular lymphoma occurrence when exceeding 19 grams of alcohol per day (one glass has approximately 14 g). Alcohol intake is also associated with different types of cancer.
• Tobacco: smokers have a higher risk of developing follicular lymphoma.
• Medical history: disorders with depression of the immune system are also associated with follicular lymphomas, such as HIV/AIDS, autoimmune diseases, or different medications [2].

Treatment

Different types of treatment may be used for follicular lymphoma:

• Radiation therapy. Radiation therapy is one of the most common cancer treatments, destroying cancer cells forming in the nodes. Radiation therapy should be given after delivery for pregnant women with follicular lymphoma to avoid any risk to the baby. 
• Chemotherapy. Chemotherapy is another widely used treatment for follicular lymphoma in which drugs disrupt the formation of cancer cells, either by destroying or preventing them from multiplying. 
• Immunotherapy. In this case, the immune system is used to fight follicular lymphoma. Using substances made by the body or produced in a laboratory seeks to restore the body’s defenses to fight cancer. 
• Targeted therapy. Targeted therapy is a type of treatment that uses drugs or other substances to identify and attack specific cancer cells. Targeted therapies generally cause less damage to normal cells than different types of treatment. 
• Surgery. Surgery is sometimes used to remove follicular lymphoma.
• Stem cell transplantation. After radiation therapy or chemotherapy, stem cells, either taken from the patient himself or a donor, replace the cells destroyed in the treatment [5].

Does genetics play a role in follicular lymphoma?

Follicular lymphoma doesn’t have a genetic origin, although some studies show some degree of influence. Some 90% of follicular lymphomas present a translocation between chromosomes 14 and 18, that is, a displacement of a fragment of one chromosome to the other, which is considered the initial genetic event in the development of this lymphoma [6]. 

In addition, genetic mutations are responsible for modifying the composition and structure of the lymphoma, as well as the predisposition to suffer from this disease in the BCL2, CXCR5, and SLC14A2 genes, among others [2012]. Furthermore, these genetic mutations alter the microenvironment, thus producing the appearance of lymphoma cells [6].

You can find out if your genetic predisposition to follicular lymphoma is higher or lower than the population through a genetic health test and, in addition, find out your propensity to many other types of diseases. At 24Genetics, we prepare reports with complete results so that you can learn about different aspects of health and well-being. Preventive medicine is essential in the treatment of diseases. Buy the test on our website and find out what your DNA says about you.

Bibliography

1. Lymphatic system. MedlinePlus in English. [accessed March 2023] Available at: https://medlineplus.gov/spanish/ency/article/002247.htm 
2. Follicular lymphoma: a guide for patients Information for patients based on the ESMO clinical guideline. [accessed March 2023]. Available at: https://www.esmo.org/content/download/52239/963515/1/ES-Linfoma-Folicular-Guia-Para-Pacientes.pdf
3. Biological aspects of follicular lymphoma. Dr. Daniel Martínez Hernández and Dr. Elías Campo Güerri. [accessed March 2023]. Available at: http://www.leucemiaylinfoma.com/modulos/CH/2013/Capitulo_1-I_2013.pdf 
4. Non-Hodgkin’s lymphoma – Symptoms and causes. Mayo Clinic. [accessed March 2023]. Available at: https://www.mayoclinic.org/es-es/diseases-conditions/non-hodgkins-lymphoma/symptoms-causes/syc-20375680 
5. Treatment of adult non-Hodgkin’s lymphoma. National Cancer Institute. [accessed March 2023]. Available at: https://www.cancer.gov/espanol/tipos/linfoma/paciente/tratamiento-lnh-adultos-pdq 
6. Follicular lymphoma: from genetics to clinical practice. Onco Americas. [accessed March 2023]. Available at: https://www.oncoamericas.com/es/linfoma-folicular-de-genetica-a-practica-clinica/