Non-Hodgkin Lymphoma
Non-Hodgkin Lymphoma (NHL) describes a group of cancers arising from lymphocytes, a type of white blood cell. It is distinct from
Hodgkin lymphoma in its pathologic
features, epidemiology, common sites of involvement, clinical behavior, and treatment. The non-Hodgkin lymphomas are a diverse group of diseases with varying courses,
treatments, and prognoses.
Non-Hodgkin lymphoma may develop in any organ associated with the lymphatic system (e.g. spleen, lymph nodes, or tonsils). Most cases start with infiltration of lymph nodes,
but some subtypes may be restricted to other lymphatic organs.
The diagnosis of non-Hodgkin lymphoma requires a biopsy of involved tissue. The numerous subtypes of non-Hodgkin lymphoma are typically grouped into three distinct
categories based on their aggressiveness, or histologic grade. These categories are indolent (or low-grade), aggressive (or intermediate-grade), and highly aggressive (or
high-grade). The treatment of indolent or low-grade
lymphoma may initially involve a period of observation, while aggressive or highly aggressive non-Hodgkin lymphoma is
typically treated with chemotherapy and/or radiation therapy.
Current Research
For current research articles click
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Symptoms
The most common symptom of non-Hodgkin's lymphoma is a painless swelling of the lymph nodes in the neck, underarm (axilla), or groin.
Other symptoms may include the following:
- Unexplained fever
- Unexplained weight loss and anorexia (poor appetite)
- Constant fatigue
- Itchy skin
- Reddened patches on the skin
Such symptoms are non-specific and may be caused by other, less serious conditions.
Diagnosis
If non-Hodgkin's lymphoma is suspected, the doctor asks about the person's medical history and performs a physical exam. The exam includes feeling to see if the lymph nodes
in the neck, underarm, or groin are enlarged. In addition to checking general signs of health, the doctor may perform blood tests.
The doctor may also order tests that produce pictures of the inside of the body. These may include:
- X-rays: Pictures of areas inside the body created by high-energy radiation.
- CT scan (computed tomography scan, also known as a "CAT scan"): A series of detailed pictures of areas inside the body. The pictures are created by a computer
linked to an x-ray machine.
- PET scan (positron emission tomography scan): This is an imaging test that detects uptake of a radioactive tracer by the tumor. More often, the PET scan can be
combined with the CT scan.
- MRI (magnetic resonance imaging): Detailed pictures of areas inside the body produced with a powerful magnet linked to a computer.
Less commonly used
- Lymphangiogram: Pictures of the lymphatic system taken with x-rays after a special dye is injected to outline the lymph nodes and vessels. This test is not used as
often because of the adoption of CT scan and the PET scan technologies.
- Gallium scan: Gallium is a rare metal that behaves in the body in a fashion similar to iron, so that it concentrates in areas of inflammation or rapid cell-division, and
hence is useful for imaging the entire lymphatic system for staging of lymphoma once the presence of the disease has been confirmed. PET scans have
supplanted gallium scans for evaluation and follow up of NHL.
Biopsy
A biopsy is needed to make a diagnosis. A surgeon removes a sample of tissue, which a pathologist can examine under a microscope to check for
cancer cells. A biopsy for
non-Hodgkin's lymphoma is usually taken from lymph nodes that are enlarged, but other tissues may be sampled as well. Biopsies in internal lymph nodes can also taken as
needle biopsies under the guidance of CT scans. Rarely, an operation called a laparotomy may be performed. During this operation, a surgeon cuts into the abdomen and
removes samples of tissue to be checked under a microscope.
Types of Non-Hodgkin's Lymphoma
Over the years, doctors have used a variety of terms to classify the many different types of non-Hodgkin's lymphoma . Most often, they are grouped by how the
cancer cells look
under a microscope and how quickly they are likely to grow and spread. Aggressive
lymphomas, also known as intermediate and high-grade
lymphomas, tend to grow and spread
quickly and cause severe symptoms. Indolent
lymphomas, also referred to as low-grade lymphomas, tend to grow quite slowly and cause fewer symptoms. One of the paradoxes
of non-Hodgkin's lymphoma is that the indolent lymphomas generally cannot be cured by chemotherapy, while in a significant number of cases aggressive lymphomas can be.
Current
lymphoma classification is complex.
Common types of lymphomas include follicular lymphoma, which tends to be indolent, and diffuse large B cell lymphoma, an aggressive form of NHL.
Details of the most popular classifications of
lymphoma can be found in the
lymphoma page.
Causes
The etiology, or cause, of most
lymphomas is not known. Some types of lymphomas are associated with viruses. Burkitt's lymphoma, extranodal NK/T cell lymphoma, classical
Hodgkin's disease and most
AIDS-related lymphoma are associated with Epstein-Barr virus. Adult T-cell lymphoma/
leukemia, endemic in parts of Japan and the Caribbean, is
caused by the HTLV-1 virus. Lymphoma of the stomach (extranodalabcde marginal zone B-cell lymphoma) is often caused by the Helicobacter bacteria.
The incidence of non-Hodgkin's lymphoma has increased dramatically over the last couple of decades. This disease has gone from being relatively rare to being the fifth most
common
cancer in the United States. At this time, little is known about the reasons for this increase or about exactly what causes non-Hodgkin's lymphoma.
Doctors can seldom explain why one person gets non-Hodgkin's lymphoma and another does not. It is clear, however, that
cancer is not caused by an injury, and is not contagious;
no one can "catch" non-Hodgkin's lymphoma from another person.
By studying patterns of
cancer in the population, researchers have found certain risk factors that are more common in people who get non-Hodgkin's lymphoma than in those who
do not. However, most people with these risk factors do not get non-Hodgkin's lymphoma, and many who do get this disease have none of the known risk factors.
The following are some of the risk factors associated with this disease:
- Age/sex. The likelihood of getting non-Hodgkin's lymphoma increases with age and is more common in men than in women.
- Weakened immune system (AIDS-related lymphoma). Non-Hodgkin's lymphoma is more common among people with inherited immune deficiencies, autoimmune
diseases, or HIV/AIDS, and among people taking immunosuppressant drugs following organ transplants. (see Post-transplant lymphoproliferative disorder)
- Viruses. Human T-lymphotropic virus type I (HTLV-1) and Epstein-Barr virus are two infectious agents that increase the chance of developing non-Hodgkin's lymphoma.
- Environment. People who work extensively with or are otherwise exposed to certain chemicals, such as pesticides, solvents, or fertilizers, have a greater chance of
developing non-Hodgkin's lymphoma.
People who are concerned about non-Hodgkin's lymphoma should talk with their doctor about the disease, the symptoms to watch for, and an appropriate schedule for checkups.
The doctor's advice will be based on the person's age, medical history, and other factors.
Staging
If non-Hodgkin's lymphoma is diagnosed, the doctor needs to learn the stage, or extent, of the disease. Staging is a careful attempt to find out whether the
cancer has spread and,
if so, what parts of the body are affected. Treatment decisions depend on these findings.
The doctor considers the following to determine the stage of non-Hodgkin's lymphoma:
- The number and location of affected lymph nodes
- Whether the affected lymph nodes are above, below, or on both sides of the diaphragm (the thin muscle under the lungs and heart that separates the chest from
the abdomen)
- Whether the disease has spread to the bone marrow, spleen, or to organs outside the lymphatic system, such as the liver; and the testes
- Whether B symptoms (systemic symptoms) such as fever, chills, night sweats, or weight loss are present.
In staging, the doctor may use some of the same tests used for the diagnosis of non-Hodgkin's lymphoma. Other staging procedures may include additional biopsies of lymph
nodes, the liver, bone marrow, or other tissue. A bone marrow biopsy involves removing a sample of bone marrow through a needle inserted into the hip or another large bone.
A pathologist examines the sample under a microscope to check for
cancer cells.
Stages of NHL
The various stages of NHL (the Ann Arbor staging classification, developed for
Hodgkin's lymphoma) are based on how far the
cancer has spread throughout and beyond the
lymphatic system, and whether constitutional symptoms (fever, night sweats, or weight loss) are present.
Stage I
"Stage I" indicates that the cancer is located in a single region, usually one lymph node and the surrounding area. Stage I often will not have
outward symptoms.
Stage II
"Stage II" indicates that the cancer is located in two separate regions, an affected lymph node or organ within the lymphatic system and a second
affected area, and that both affected areas are confined to one side of the diaphragm - that is, both are above the diaphragm, or both are below the diaphragm.
Stage III
"Stage III" indicates that the cancer has spread to both sides of the diaphragm, including one organ or area near the lymph nodes or the spleen.
Stage IV
"Stage IV" indicates that the cancer has spread beyond the lymphatic system and involves one or more major organs, possibly including the
bone marrow or skin.
The absence of constitutional symptoms is denoted by adding an "A" to the stage; the presence is denoted by adding a "B" to the stage (hence the name B symptoms).
Staging in non-Hodgkin's lymphomas is far less significant in determining therapy than it is in
Hodgkin's lymphoma
Prognosis
The most significant factor in overall prognosis is the grade, or aggressiveness, of the
lymphoma. Indolent (low-grade) non-Hodgkin's lymphoma is generally not curable, but is
typically slowly progressive and responds temporarily to therapy. Aggressive and highly aggressive (intermediate- and high-grade) NHL's are potentially curable with combination
chemotherapy. Long-term survival or cure rates for these diseases vary with a number of prognostic factors.
International Prognostic Index
The International Prognostic Index, or IPI, is the most widely used prognostic system for non-Hodgkin's lymphoma. This system uses 5 factors:
- Age
- Lactate dehydrogenase level (a blood test)
- Performance status
- Clinical stage
- Sites of extranodal disease
However, it should be noted that the IPI was developed prior to the introduction of rituximab. As rituximab has become a standard part of therapy for B-cell NHL's, the impact on the
prognostic value of the IPI is unclear.
FLIPI
For the subtype of NHL known as follicular lymphoma, a modified version of the IPI called the FLIPI (follicular lymphoma international prognostic index) has been developed. The
factors which figure into the FLIPI are age, clinical stage, lactate dehydrogenase level, hemoglobin level, and number of nodal sites involved. As with the IPI, the FLIPI was
developed and validated prior to the widespread use of rituximab, so the same caveats apply as were mentioned with the IPI above.
Treatment
The doctor develops a treatment plan to fit each patient's needs. Treatment for non-Hodgkin's lymphoma depends on the stage of the disease, the type of cells involved, whether
they are indolent or aggressive, and the age and general health of the patient.
Non Hodgkin's lymphoma is often treated by a team of specialists that may include a hematologist, medical oncologist, and/or radiation oncologist. Non-Hodgkin's lymphoma is
usually treated with chemotherapy, radiation therapy, or a combination of these treatments. In some cases, bone marrow transplantation, biological therapies, or surgery may be
options. For indolent
lymphomas, the doctor may decide to wait until the disease causes symptoms before starting treatment. Often, this approach is called "watchful waiting."
Taking part in a clinical trial (research study) to evaluate promising new ways to treat non-Hodgkin's lymphoma is an important option for many people with this disease.
Chemotherapy and Radiation Therapy
Chemotherapy and radiation therapy are the most common treatments for non-Hodgkin's lymphoma, although bone marrow transplantation, biological therapies, or surgery are
sometimes used. CHOP, with rituximab added in certain circumstances, is the most commonly used combination of chemotherapy.
Rituximab is an antibody-based therapy. Zevalin and Bexxar are government-approved options, requiring a Nuclear Medicine facility, but only two shots 1 week apart. There is
mounting evidence that more patients have long-term remission if they use radioimmunotherapy first.
Radiation therapy (also called radiotherapy) is the use of high-energy rays to kill
cancer cells. Treatment with radiation may be given alone or with chemotherapy. Radiation therapy
is local treatment; it affects cancer cells only in the treated area. Radiation therapy for Non Hodgkin's lymphoma comes from a machine that aims the high-energy rays at a specific
area of the body. There is no radioactivity in the body when the treatment is over.
Sometimes patients are given chemotherapy and/or radiation therapy to kill undetected
cancer cells that may be present in the central nervous system (CNS). In this treatment,
called central nervous system prophylaxis, the doctor injects anticancer drugs directly into the cerebrospinal fluid.
Hematopoietic Stem Cell Transplantation
Hematopoietic stem cell transplantation (HSCT), or Bone marrow transplantation (BMT) may also be a treatment option, especially for patients whose non-Hodgkin's lymphoma
has recurred (come back). BMT provides the patient with healthy stem cells (very immature cells, found in the marrow, that produce blood cells), the function of which is to replace
white blood cells that are damaged or destroyed by treatment with very high doses of chemotherapy and/or radiation therapy. The healthy bone marrow may come from a donor,
or it may be "autologous" (marrow that was removed from the patient, stored, and then given back to the person following the high-dose treatment). Autologous transplants are
preferred, as the recipient is less likely to reject the cells, the origins of which were the same entity. However, in order for an autologous transplant to be performed, certain
physiological conditions must be optimal within the patient. If these conditions are not present, transplanted stem cells can come from other donors. Until the transplanted bone
marrow begins to produce enough white blood cells, patients have to be carefully protected from infection due to the virtual elimination of the auto-immune system resulting from
the high-intensity treatment. Without the introduction of the stem cells following the high dose treatment, the patient will not survive as the body will be unable to produce
infection-fighting white blood cells. Patients usually stay in the hospital for several weeks and will be monitored for transplant rejection and overall health.
Immunotherapy
Biological therapy (also called immunotherapy) is a form of treatment that uses the body's immune system, either directly or indirectly, to fight
cancer or to lessen the side effects
that can be caused by some
cancer treatments. It uses materials made by the body or made in a laboratory to boost, direct, or restore the body's natural defenses against disease.
This approach is under close investigation. Biological therapy is sometimes also called biological response modifier therapy.
Measuring Response to Treatment
After treatment for non-Hodgkin's lymphoma, the response is classified as follows:
- Complete Response (CR). This indicates the disappearance of all detectable disease.
- Partial Response (PR). A reduction in the bulk of disease by at least 50%, but with some remaining disease.
- Stable Disease. Less than a partial remission, but no progression of disease and no new sites of disease.
- Progressive Disease. Growth in bulk of disease by >50%, or the appearance of new sites of disease.
If a complete remission is achieved, the patient is watched closely for any evidence of recurrent disease. Standard guidelines dictate that a patient be monitored for relapse every
three months in the first year following a complete remission, every six months in the second year, and finally once annually in the third and later years. Diffuse large b-cell
lymphoma is the most common type of lymphoma that is considered curable. Currently, if a patient maintains a complete remission for 3 years, the patient is considered
cured. Generally most relapses of diffuse large b-cell lymphoma occur within the first year after a complete remission is obtained. Reoccurences after 3 years are rare but
they do occur. The effect of Rituximab on relapse rates for diffuse large b-cell lymphoma is still largely unknown, though initial relapse rates since 2003 have been much lower
than expected.
Patients with follicular lymphoma are generally not considered cured. Instead, they are categorized as in ongoing complete remission. Relapses occur steadily over time. Relapse
rates are estimated to be 33%, 66%, and 100% for follicular lymphoma's Grades I, II, and III respectively.
Research has indicated that relapse rates can be lowered on patients with follicular lymphoma by giving supplemental radiation therapy, however, it is known that this additional
therapy increases the chances of a second malignancy of unknown type later in life.
If the response to treatment falls short of a complete response, more treatment may be administered (using a different chemotherapy regimen), or watchful waiting may be utilized,
depending on the goals of treatment.
Nutrition during treatment
Eating well during
cancer treatment means getting enough food energy and protein to help prevent weight loss and regain strength. Good nutrition often helps people feel better
and have more energy.
Some people with
cancer find it hard to eat a balanced diet because they may lose their appetite. In addition, common side effects of treatment, such as nausea, vomiting, or mouth
sores, can make eating difficult. Often, foods may taste or smell different. Also, people being treated for cancer may not feel like eating when they are uncomfortable or tired.
Doctors, nurses, and dietitians can offer advice on how to get enough food energy and protein during cancer treatment. Patients and their families also may want to read the
National Cancer Institute (USA) booklet Eating Hints for
cancer Patients, which contains many useful suggestions.
Followup Care
People who have had non-Hodgkin's lymphoma should have regular followup examinations after their treatment is over. Followup care is an important part of the overall
treatment plan, and people should not hesitate to discuss it with their health care provider. Regular followup care ensures that patients are carefully monitored, any changes
in health are discussed, and new or recurrent
cancer can be detected and treated as soon as possible. Between followup appointments, people who have had Non Hodgkin's
lymphoma should report any health problems as soon as they appear.
Followup Care
Notable persons treated for non-Hodgkin's lymphoma include:
- The former Shah Mohammed Reza Pahlavi of Iran (although this was probably chronic lymphocytic leukemia)
- Jacqueline Kennedy Onassis, widow of former U.S. president John F. Kennedy
- Tim Tobias, jazz pianist
- Gene Wilder, diagnosed in 1999, made a full recovery in 2000
- U.S. Senator Paul Tsongas
- Fred Dalton Thompson, former United States Senator, actor and potential 2008 presidential candidate
- Hussein of Jordan, former king of Jordan
- British soap opera star Anne Kirkbride
- Velvet Underground guitar player Sterling Morrison
- Australian opera and musical theatre star Anthony Warlow
- Golda Meir former prime minister of Israel
- U.S. Nobel Prize laureate Jack S. Kilby, inventor of the integrated circuit
- Croatian basketball player, coach, and diplomat Krešimir Ćosić
- Saku Koivu, NHL star, captain of the Montreal Canadiens
- British politician Menzies Campbell
- American political commentator and movie critic Steve Sailer, diagnosed with Stage IV NHL in 1997, made a full recovery after getting into a clinical trial, and has
been cancer-free ever since
- Ernie Johnson Jr., American sports broadcaster for TNT and TBS
- Andres Galarraga, MLB first baseman
- Joey Ramone, lead singer for The Ramones
- Saul Bass, American graphic designer
- Scott Rentrop, professional stuntman of Louisiana
- Jon Lester, Boston Red Sox pitcher
- David Rocastle, English footballer
- Cesar Castillo, American Actor
- John Hartford, American country / bluegrass composer and musician. Died June 4, 2001; after long battle with NHL
- Mike Tetrault, blues musician
- Bruce Gary, famed rock drummer (The Knack, My Sharona). Died Aug 22, 2006 from NHL.
- John Cullen, NHL star, played for and captained the Pittsburgh Penguins, Hartford Whalers, Toronto Maple Leafs, and the Tampa Bay Lightning
(adapted from Wikipedia, the free encyclopedia http://en.wikipedia.org/wiki/Non-Hodgkin%27s_Lymphoma)
Authors: Macklis RM.
Cleveland Clinic Lerner College of Medicine and Department of Radiation Oncology, Cleveland Clinic Foundation, Cleveland, OH.
Radioimmunotherapy (RIT) represents a relatively new antibody-based radiopharmaceutical treatment for patients with various kinds of tumors. Although the field has a long
history of preclinical and clinical investigations using many different agents, to date, only 2 of these immunologically targeted radiopharmaceuticals have been cleared for
commercial sale. Both of these agents ((90)Y-ibritumomab tiuxetan or "Zevalin" [Biogen-Idec, Boston, MA] and (131)I-tositumomab or "Bexxar" [GlaxoSmithKline Research,
Triangle Park, NC]) are directed against the CD20 surface antigen found on normal mature B cells and greater than 95% of B-cell non-Hodgkin lymphoma (NHL). Both compounds
produce similar impressive clinical outcomes (approximately 20%-40% complete response rates and 60%-80% overall response rates for patients with indolent B-cell NHL).
Current protocol-based investigations of anti-CD20 RIT relate to new clinical uses and new CD20(+) targets.
Journal: Semin Radiat Oncol. 2007 Jul;17(3):176-83
Authors: Cozen W, Cerhan JR, Martinez-Maza O, Ward MH, Linet M, Colt JS, Davis S, Severson RK, Hartge P, Bernstein L.
Department of Preventive Medicine and Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, 1441 Eastlake Ave, MC 9175, Los Angeles, CA, 90089-9175, USA.
OBJECTIVE: Since adult immune responsiveness is influenced by early childhood exposures, we examined the role of family size, history of atopic disease, and other childhood
immune-related exposures in a multi-center case-control study of NHL. METHODS: Interviews were completed with 1,321 cases ascertained from population-based
registries in Seattle, Detroit, Los Angeles and Iowa, and with 1,057 frequency-matched controls, selected by random-digit dialing and from the Medicare files database. Multivariable
logistic regression was used to estimate risk. RESULTS: A history of any
(excluding drug allergies), decreased risk of all NHL (Odds Ratio [OR] = 0.7, 95% Confidence
Interval [CI] = 0.6-1.0), diffuse large B-cell lymphoma [DLBCL] (OR = 0.6, 95% CI = 0.4-0.9), and follicular NHL (OR = 0.7, 95 CI = 0.5, 1.0). A similar effect was observed for hay
fever. A history of eczema was associated with an increased risk of follicular lymphoma (OR = 1.9, 95% CI = 1.1-3.4), but not DLBCL (OR = 1.1, 95% CI = 0.6-2.0).
did not
affect risk. Youngest compared to oldest siblings had a 90% increased risk of DLBCL (95% CI = 1.2-3.1; p for trend with increasing birth order = 0.006), but not follicular
lymphoma (OR = 1.1, 95% CI = 0.6-1.8). CONCLUSIONS: We infer that some childhood and immune-related factors may alter NHL risk.
Journal: Cancer Causes Control. 2007 Jun 22
Authors: Polesel J, Dal Maso L, La Vecchia C, Montella M, Spina M, Crispo A, Talamini R, Franceschi S.
Unita di Epidemiologia e Biostatistica, Centro di Riferimento Oncologico, Aviano, Italy.
Dietary deficiency of folate and other micronutrients involved in the one-carbon metabolism (i.e., vitamins B2, B6, B12, and methionine) have been related to several diseases,
including cancers, but results on non-Hodgkin lymphoma (NHL) are controversial. A hospital-based case-control study was conducted in Italy, in 1999-2002. Cases were 190
incident, histologically confirmed NHL aged 18-84 years. Controls were 484 subjects admitted to hospitals for acute, non-neoplastic diseases supposed to be unrelated to alcohol
consumption or to diet modification. Dietary habits, including alcohol drinking, were assessed by a validated food-frequency questionnaire. Nutrient intakes were computed using
the Italian food composition database. Odds ratios (ORs) and corresponding 95% confidence intervals for tertiles of nutrients' intake were computed using the energy-adjusted
residual models. No significant association emerged between NHL risk and intakes of folate (OR = 0.9), vitamin B2 (OR = 0.9), vitamin B6 (OR = 0.8), and methionine (OR = 0.7).
However, a significant inverse association was observed for all the nutrients examined among abstainers and former drinkers, whereas no relations between one-carbon
nutrients and NHL risk emerged among current alcohol drinkers. Our findings support the possibility of an antagonist effect of alcohol on the one-carbon metabolism in NHL
etiology. However, the lack of an overall effect for one-carbon nutrients and the small sample size suggested caution in interpreting our results.
Journal: Nutr Cancer. 2007;57(2):146-50.
Authors: DeMonaco NA, McCarty KS, Joyce J, Jacobs SA.
Department of Hematology/Oncology, University of Pittsburgh Cancer Institute, Pittsburgh, PA 15232, USA.
A 75-year-old man with relapsed follicular non-Hodgkin lymphoma confined to a solitary lung mass was treated with radioimmunotherapy (RIT) using yttrium 90-ibritumomab
tiuxetan. Imaging with positron emission tomography/computed tomography showed a complete response 3 months after RIT. Thirteen months after RIT, his positron emission
tomography/computed tomography scan showed a fluorodeoxyglucose-avid infiltrate in the area of the previous lung mass. Bronchoscopy revealed the area to be obstructed with
fibrosis, and cytologic washings and brushings did not show lymphoma. The patient remains asymptomatic, and the fluorodeoxyglucoseavid pulmonary infiltrate was unchanged
19 months after RIT. In view of the lack of respiratory symptoms or progressive imaging abnormalities, we believe radiation fibrosis is the most likely etiology. Radiation-induced
lung injury after therapy with yttrium 90 was previously reported in the setting of intraarterial microspheres used to treat inoperable hepatic tumors. This is the first case in which
radiation-induced radiographic changes are reported after RIT for
.
Journal: Clin Lymphoma Myeloma. 2007 Mar;7(5):369-72
Authors: Novik KL, Spinelli JJ, Macarthur AC, Shumansky K, Sipahimalani P, Leach S, Lai A, Connors JM, Gascoyne RD, Gallagher RP, Brooks-Wilson AR.
Genome Sciences Centre, British Columbia Cancer Research Centre, Vancouver, British Columbia, Canada V5Z 1L3.
Non-Hodgkin lymphoma (NHL) comprises a group of lymphoid tumors that have in common somatic translocations. H2AFX encodes a key histone involved in the detection of the
DNA double-stranded breaks that can lead to translocations. H2afx is a dosage-dependent gene that protects against B-cell lymphomas in mice, making its human orthologue an
ideal candidate gene for susceptibility to
. We did a population-based genetic association study of H2AFX variants in 487 NHL cases and 531 controls. Complete
resequencing of the human H2AFX gene in 95 NHL cases was done to establish the spectrum of variation in affected individuals; this was followed by both direct and indirect
tests for association at the level of individual single nucleotide polymorphisms (SNP) and as haplotypes. Homozygosity for the AA genotype of a SNP 417 bp upstream of the
translational start of H2AFX is strongly associated [odds ratio (OR), 0.54; P = 0.001] with protection from NHL. We find a strong association of this SNP with the follicular lymphoma
subtype of NHL (AA genotype: OR, 0.40; P = 0.004) and with mantle cell lymphoma (AA genotype: OR, 0.20; P = 0.01) that remains significant after adjustment for the false discovery
rate, but not with diffuse large B-cell lymphoma. These data support the hypothesis that genetic variation in the H2AFX gene influences genetic susceptibility or resistance to some
subtypes of NHL by contributing to the maintenance of genome stability.
Journal: Cancer Epidemiol Biomarkers Prev. 2007 Jun;16(6):1098-106.
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