Epidemiology Etiology

Of Lymphoma

Dr.Azarm

Epidemiology

In the United States, approximately

55,000 new cases of non-Hodgkin’s lymphoma are diagnosed annually,

and about 25,000 people die of the

disease each year.

The incidence of non-Hodgkin's lymphoma (NHL) has doubled over the past two decades in the US and most other westernized countries

Epidemiology

Dr.Azarm

The annual incidence of non-Hodgkin lymphoma has nearly

doubled over the last 55 years

Dr.Azarm

Up to 35 to 65 percent of Poorly - differentiated

neoplasms of unknownprimary site may representcases of NHL

Dr.Azarm

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LymphomaLung

BladderBlood

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Cancer in Men

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The etiology is unknown -Genetic,

-Environmental , -Infectious agents have been implicated .

-Familial clusters have been described, and there may be a slightly higher risk of non-Hodgkin’s lymphoma among siblings or first-degree relatives of patients with lymphoma or other hematologic

malignancies.

:Etiology

Dr.Azarm

Ultraviolet (UV) irradiation may cause immunosuppression However,

studies that have especially evaluated the possible role of UV light in NHL have shown an increased risk for outdoor occupations or exposure to sunlight

Etiology:

Epstein-Barr virus:It has been associated with Burkitt lymphoma.

EBV is persistent in over 95% of adults in nasopharyngeal epithelium and B cells Normally, EBV production is held back by active cellular and humoral immune

mechanisms .In immunodeficiency states, this balance may be disrupted, and EBV-infected B cells begin to proliferate.

Specific illnesses which are risk factors for the development of gastrointestinal lymphoma include

Crohn's disease Gastrointestinal nodular lymphoid hyperplasia Helicobacter pylori-associated chronic gastritis Celiac diseas

Ethiologic factors in NHLEthiologic factors in NHL

_ TCR_ Congenital Immunodeficiency s._ Aquaired. I . d._ Auto-immune disorders_ Viral cofactors: Epstein Barr Virus HIV HTLV-1 Herpes Virus Helicobacter Pylori

_ Organ Transplantation

blood transfusion immunosuppression , and transmission of viruses have been discussed Increased incidence of NHL.

It has been reported among patients with: :congenital immune deficiency. - Autoimmune

Rheumatoid arthritis. - -Sjögren's syndrome.

. -Systemic lupus erythematosus Therapy. - immunosuppressive

Chemotherapy and radiotherapy regimens in patients with Hodgkin's disease.

Dr.Azarm

The insecticide chlordane, significantly higher concentrations were found in NHL cases than in controls in the same study the sum of chlordanes in the 27 NHL patients was 180 ng/g lipid compared to 92.8 in the 17 surgical controls

Etiology::

Infections:-Infection with HIV

Infection with human T-lymphocytic virus type 1 (HTLV-1)-Infection with Epstein-Barr virus (EBV), one of the etiologic

factors in Infectous mononucleosis .-A bacterium that lives in the digestive Helicobacter pylori

-Autoimmune disease-Diseases requiring immune suppressive therapy, often used

following organ transplant .-Inherited immunodeficiency diseases (severe combined

immunodeficiency, ataxia telangiectasia , -

MALIGNANCYMALIGNANCY due to EBVdue to EBV

Burkitt's lymphoma (NHL)

Hodgkin's disease

Nasopharyngeal carcinoma

T cell lymphoma

Nasal/nasal type angiocentric lymphoma

Oncogenic viruses :Oncogenic viruses :

The infection of cells by oncogenic viruses must be considered to be a genetic lesion, since viruses introduce foreign genes into their target cells. Three distinct viruses are associated with the

pathogenesis of specific NHL subtypes .

-Epstein-Barr virus (EBV)-Human T-cell lymphotropic virusI (HTLV-I)-Human Herpes virus-8 (HHV-8)-Simian virus 40

Simian virus 40Simian virus 40

Simian virus-40 (SV-40) is a polyoma virus with oncogenic potential in humans and animals. Its actions are thought to result from inactivation of tumor suppressors p53

AIDS-related lymphomas:AIDS-related lymphomas: (AIDS-NHL) are invariably derived from B-cells and are classified into 3 main groups:

1- AIDS-related BL (AIDS-BL) .

2- AIDS-related DLBCL (AIDS-DLBCL).

3- AIDS-related body-cavity-based lymphomas

(AIDS-BCL) represent a rare additional type of AIDS-NHL.

Ultraviolet radiation ,previously demonstrated to have an immunosuppressive effect, has also been suggested as a possible risk factor for NHL

Factors thought to increase risk of lymphoma include:  

 

 

Chemical exposures -dioxins, PCBs, pesticides, solvents, and fertilizer 

 

 

Chronic infections -H pylori is strongly

 

 

Depressed immunity - such as caused by immune-suppressing drugs used to prevent rejection of organ transplants

People infected with the hepatitis C virus (HCV) are at an increased risk of developing certain lymphomas

Factors Associated with the development of Non-Hodgkin’s Lymphoma

1- Immune abnormalities: Inherited disorders Common variable immunodefeciency , Wiskott-Aldrich syndrome Ataxia-telangictasia , X-linked lymphoprolifrative disorder

Acquired disorders: Solid organ transplant recipients Acquired immunodeficiency syndrome Methotrexate therapy for autoimmune disorders Rheumatoid arthritis , Sjogren’s syndrome , Hashimoto’s thyroiditis

2- Infectious agents: Epestein – Barr Virus Human T-cell lymphotropic virus type ! , Human herpes virus 8 Hepatitis C Virus, Helicobacter pylori

3- Occupational and environmental exposure: Herbicides, Organic Solvents, Hair dyes, Ultraviolet light