Skip to content
Inciteful Med

The Biology of Your Cells: Why Follicular Lymphoma Happens

Last updated:

To understand follicular lymphoma (FL), it helps to think of your body’s cells as having an “instruction manual.” In FL, a specific error in this manual causes certain white blood cells to “forget” how to die. This allows them to build up over time, forming the clusters we see as enlarged lymph nodes [1][2].

The Biology: A Broken “Off Switch”

The journey of follicular lymphoma usually begins with a genetic mistake called a translocation. Specifically, it is known as the t(14;18) translocation [3][4].

  • What happens: Two pieces of DNA that shouldn’t be next to each other get swapped. This places a gene called BCL2 next to a very active “promoter” [3][1].
  • The Result: The cell produces too much BCL2 protein. In a healthy cell, BCL2 is part of the system that controls apoptosis—or programmed cell death [5][6].
  • The Problem: Think of BCL2 as a shield that prevents the “off switch” from being flipped. Because these cells don’t die when they are supposed to, they continue to survive and accumulate [5][7].

It is important to know that this translocation alone isn’t enough to cause cancer. In fact, many healthy people carry these “pre-cancerous” cells without ever getting sick [3][8]. To become follicular lymphoma, the cells must undergo a multi-step process, moving from the bone marrow to the lymph nodes and acquiring “secondary hits”—additional genetic mutations that drive the disease forward [9][10][11].

How It Feels: Recognizing Symptoms

Because follicular lymphoma is indolent (slow-growing), symptoms often develop very gradually over months or even years [12][13].

Common Physical Signs

  • Painless Lymphadenopathy: The most common sign is one or more painless, firm, and rubbery swellings in the neck, armpit, or groin [14][15]. Unlike nodes enlarged by an infection, these typically do not hurt and do not go away on their own.
  • Abdominal Fullness: Sometimes, the lymphoma involves the spleen (splenomegaly) or creates a mass in the abdomen. This can make you feel “full” quickly after eating or cause a dull ache in the upper left side of your stomach [15][16].

Systemic “B-Symptoms”

Doctors often ask about B-symptoms, which are signs that the lymphoma is affecting your whole body [17][12]:

  • Fever: Unexplained fevers (usually above 100.4°F) that come and go.
  • Night Sweats: Drenching sweats that may require you to change your clothes or bedsheets.
  • Weight Loss: Losing more than 10% of your body weight in six months without trying.

In follicular lymphoma, B-symptoms are actually less common than in more aggressive lymphomas [17][18]. If you suddenly develop these symptoms, it can be a sign that the disease is becoming more active or is “transforming” into a faster-growing type [17][19].

The “Neighborhood”: Tumor Microenvironment

Follicular lymphoma cells do not live in isolation. They create a supportive “neighborhood” called the tumor microenvironment [20][11].

The cancer cells “recruit” healthy cells—like certain types of T-cells and support cells (follicular dendritic cells)—to help them survive [21][22]. This neighborhood helps the cancer evade the immune system by:

  • Sending out signals that “exhaust” the immune cells meant to kill them [23][24].
  • Creating a shield that makes it harder for treatments to reach the cancer cells [23].

Contrast with Aggressive Lymphomas

It is helpful to contrast FL with aggressive lymphomas like Diffuse Large B-cell Lymphoma (DLBCL). While DLBCL often appears suddenly with rapidly growing nodes and intense symptoms, follicular lymphoma is usually a “quiet” disease that moves slowly [12][25]. Knowing this can help you understand why your doctor might recommend a “watch and wait” approach rather than starting intensive chemotherapy immediately [26].

Questions for Your Doctor

  • • My biopsy mentions BCL2 overexpression and a t(14;18) translocation—can you explain if this is typical for my specific case?
  • • Are there other 'secondary' mutations you looked for in my biopsy, such as EZH2 or KMT2D?
  • • Does my PET scan show any 'high metabolic activity' (SUV) that might suggest my lymphoma is behaving more aggressively?
  • • Is my spleen enlarged, and should I be concerned about any abdominal discomfort I’m feeling?
  • • If I develop new B-symptoms (like drenching night sweats), what is the process for re-evaluating my 'watch and wait' status?

Questions for You

  • • When did I first notice my lymph nodes, and how fast have they grown? (Stable growth is often a hallmark of indolent lymphoma).
  • • Have I had any 'drenching' night sweats that required me to change my pajamas or sheets?
  • • Do I feel unusually full after eating only a small amount? (This can sometimes be a sign of an enlarged spleen).
  • • How much weight have I lost without trying? (Losing more than 10% of your body weight is a key 'B-symptom').

Want personalized information?

Type your question below to get evidence-based answers tailored to your situation.

References

  1. 1

    Correlation of t(14;18) translocation breakpoint site with clinical characteristics in follicular lymphoma.

    Panjan M, Boltezar L, Novakovic S, et al.

    Radiology and oncology 2023; (57(4)):487-492 doi:10.2478/raon-2023-0030.

    PMID: 37439703
  2. 2

    Recent advances in understanding the biology of follicular lymphoma.

    Nishikori M

    International journal of hematology 2025; (121(3)):326-330 doi:10.1007/s12185-024-03764-6.

    PMID: 38536645
  3. 3

    Precursory or early lesions of follicular lymphoma: clinical features, pathology, and genetics.

    Oishi N

    Journal of clinical and experimental hematopathology : JCEH 2023; (63(2)):65-72 doi:10.3960/jslrt.23010.

    PMID: 37380471
  4. 4

    Divergent evolution of metachronous follicular lymphoma and extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue from a common precursor.

    Tzioni MM, Wotherspoon A, Chen Z, et al.

    The Journal of pathology 2023; (261(1)):11-18 doi:10.1002/path.6143.

    PMID: 37345526
  5. 5

    Inhibiting the inhibitors: Targeting anti-apoptotic proteins in cancer and therapy resistance.

    Shahar N, Larisch S

    Drug resistance updates : reviews and commentaries in antimicrobial and anticancer chemotherapy 2020; (52()):100712 doi:10.1016/j.drup.2020.100712.

    PMID: 32599435
  6. 6

    Structural Details of BH3 Motifs and BH3-Mediated Interactions: an Updated Perspective.

    Sora V, Papaleo E

    Frontiers in molecular biosciences 2022; (9()):864874 doi:10.3389/fmolb.2022.864874.

    PMID: 35685242
  7. 7

    Preliminary evidence of imaging of chemokine receptor-4-targeted PET/CT with [68Ga]pentixafor in non-Hodgkin lymphoma: comparison to [18F]FDG.

    Pan Q, Luo Y, Zhang Y, et al.

    EJNMMI research 2020; (10(1)):89 doi:10.1186/s13550-020-00681-7.

    PMID: 32757068
  8. 8

    Prevalence of BCL-2/J(H) Translocation in Healthy African Americans.

    Colon-Otero G, Van Wier SA, Ahmann GJ, et al.

    Annals of hematology 2017; (96(1)):51-55 doi:10.1007/s00277-016-2842-4.

    PMID: 27730341
  9. 9

    Genetic evolution of in situ follicular neoplasia to aggressive B-cell lymphoma of germinal center subtype.

    Vogelsberg A, Steinhilber J, Mankel B, et al.

    Haematologica 2021; (106(10)):2673-2681 doi:10.3324/haematol.2020.254854.

    PMID: 32855278
  10. 10

    [Genetic evolution of in situ follicular neoplasia to t(14;18)-positive aggressive B-cell lymphoma].

    Vogelsberg A, Steinhilber J, Mankel B, et al.

    Der Pathologe 2021; (42(Suppl 2)):122-128 doi:10.1007/s00292-021-01011-x.

    PMID: 34671837
  11. 11

    Pathogenesis of follicular lymphoma.

    Lackraj T, Goswami R, Kridel R

    Best practice & research. Clinical haematology 2018; (31(1)):2-14 doi:10.1016/j.beha.2017.10.006.

    PMID: 29452662
  12. 12

    Dramatic radiotherapy response in a necrotic lymphoma mass: a case report.

    McNeil N, Gorayski P, Blunt D, Roos D

    Journal of medical case reports 2020; (14(1)):118 doi:10.1186/s13256-020-02438-1.

    PMID: 32718327
  13. 13

    Diagnosis and management of follicular lymphoma: A comprehensive review.

    Dada R

    European journal of haematology 2019; (103(3)):152-163 doi:10.1111/ejh.13271.

    PMID: 31270855
  14. 14

    Initial Treatment of High Tumor Burden Follicular Lymphoma.

    Freeman CL, Sehn LH

    Hematology/oncology clinics of North America 2020; (34(4)):673-687 doi:10.1016/j.hoc.2020.02.004.

    PMID: 32586573
  15. 15

    Refractory chylous ascites revealing follicular lymphoma: A case report.

    Tlili Y, Hadrich Z, Hafsi M, et al.

    International journal of surgery case reports 2024; (116()):109414 doi:10.1016/j.ijscr.2024.109414.

    PMID: 38430893
  16. 16

    Primary Splenic Follicular Lymphoma Presenting As Isolated Splenomegaly: A Case Report.

    Indukuri P, Thomas S, Mehrotra P, Shanmugam SG

    Cureus 2025; (17(10)):e93633 doi:10.7759/cureus.93633.

    PMID: 41181806
  17. 17

    A man in his forties with increasing shortness of breath.

    Tveiten H, Lehne G, Aukrust P, et al.

    Tidsskrift for den Norske laegeforening : tidsskrift for praktisk medicin, ny raekke 2020; (140(6)) doi:10.4045/tidsskr.19.0692.

    PMID: 32321231
  18. 18

    Endoscopic and Histopathological Characteristics of Gastrointestinal Lymphoma: A Multicentric Study.

    Tran QT, Nguyen Duy T, Nguyen-Tran BS, et al.

    Diagnostics (Basel, Switzerland) 2023; (13(17)) doi:10.3390/diagnostics13172767.

    PMID: 37685305
  19. 19

    [Transformation of Follicular Lymphoma into Composite Lymphoma: A Case Report and Literature Review].

    Avilés-Salas A, Peña-Carvajalino LF, Heredia-Jara AN, et al.

    Revista medica de Chile 2024; (152(4)):508-513 doi:10.4067/s0034-98872024000400508.

    PMID: 39450819
  20. 20

    Follicular lymphoma: updates for pathologists.

    Khanlari M, Chapman JR

    Journal of pathology and translational medicine 2022; (56(1)):1-15 doi:10.4132/jptm.2021.09.29.

    PMID: 34942689
  21. 21

    Unveiling the Role of the Tumor Microenvironment in the Treatment of Follicular Lymphoma.

    Blanco M, Collazo-Lorduy A, Yanguas-Casás N, et al.

    Cancers 2022; (14(9)) doi:10.3390/cancers14092158.

    PMID: 35565286
  22. 22

    The Tumor Microenvironment in Follicular Lymphoma: Its Pro-Malignancy Role with Therapeutic Potential.

    Watanabe T

    International journal of molecular sciences 2021; (22(10)) doi:10.3390/ijms22105352.

    PMID: 34069564
  23. 23

    Patient-derived follicular lymphoma spheroids recapitulate lymph node signaling and immune profile uncovering galectin-9 as a novel immunotherapeutic target.

    Dobaño-López C, Valero JG, Araujo-Ayala F, et al.

    Blood cancer journal 2024; (14(1)):75 doi:10.1038/s41408-024-01041-7.

    PMID: 38697976
  24. 24

    Follicular Lymphoma: The Role of the Tumor Microenvironment in Prognosis.

    Sugimoto T, Watanabe T

    Journal of clinical and experimental hematopathology : JCEH 2016; (56(1)):1-19 doi:10.3960/jslrt.56.1.

    PMID: 27334853
  25. 25

    Malignant lymphoma of the conjunctiva.

    Kirkegaard MM, Coupland SE, Prause JU, Heegaard S

    Survey of ophthalmology 2015; (60(5)):444-58.

    PMID: 26003619
  26. 26

    Patterns of therapy initiation during the first decade for patients with follicular lymphoma who were observed at diagnosis in the rituximab era.

    Arushi Khurana , Mwangi R, Ansell SM, et al.

    Blood cancer journal 2021; (11(7)):133 doi:10.1038/s41408-021-00525-0.

    PMID: 34274939

Stay up to date

Get notified when new research about Follicular lymphoma is published.

No spam. Unsubscribe anytime.