MZL is thought to arise due to chronic immune stimulation. This may be due to infections, autoimmunity, or genetic changes.1,2
Infections
- Hepatitis C is reported in ~22-35% of patients with NMZL, SMZL, and nongastric MALT lymphomas1
- H. pylori infection plays a critical role in the pathogenesis of gastric MALT lymphomas, and its eradication can lead to tumor remission1
Other infections that have been associated with non-gastric MALT lymphoma include: Chlamydia psittaci, Campylobacter jejuni, and Borrelia burgdorferi.1
Autoimmune Diseases
Autoimmune diseases (eg, systemic lupus erythematosus [SLE], rheumatoid arthritis) increase the risk of developing nongastric MALT lymphomas; activated B cells infiltrate and proliferate in normally non-lymphoid tissues.2
Genetic Factors
Genomic abnormalities are often present in MZL. These can arise during chronic inflammation and can create antigen-independent dysregulation of B cell proliferation.2 Some chromosomal translocations (a genetic change in which a piece of one chromosome breaks off and attaches to another chromosome) found in MZL include1:
- t(11;18)
- Most common translocation, especially in gastric and pulmonary MALT lymphomas
- Results in API2-MALT1 fusion
- Less likely to respond to H. pylori eradiation
- t(1;14)
- Present in 1-2% of MALT lymphomas
- Results in overexpression of BCL10
- Less likely to respond to H. pylori eradiation
- t(14;18)
- Present in 15-20% of MALT lymphomas
- Results in deregulated expression of MALT1
- t(3;14)
- Results in upregulation of FOXP1
MALT, mucosa-associated lymphoid tissue.