18. Genetics of lymphoma Flashcards
How is lymphoma characterised?
Accumulation of mature B & T lymphocytes in lymph nodes - form tumours
Lymphocytes have uncontrolled proliferation & are anti-apoptotic
How is Hodgkin’s lymphoma characterised?
Reed-Sternberg cells of B lymphoid lineage
What is the main risk factor for Hodgkin’s lymphoma?
Epstein Barr virus detected in >50% of cases
What is the prognosis of Hodgkin’s lymphoma?
Good as initially confined to single peripheral node region
How is non-Hodgkin’s lymphoma characterised?
No Reed-Sternberg cells
85% B cell, 15% T cell
Significant proportion of patients develop extranodal disease (in other tissues)
What is the genetic cause of the majority of NHL?
Translocations involving immunogloblin genes - occur due to errors in VDJ recombination of IG genes in bone marrow
What is the clinical phenotype of Burkitt lymphoma?
High grade - acute & aggressive
Large lumps at extra nodal sites such as jaw, abdomen, bowel
What are the 3 sub-types of BL?
- Sporadic
- Endemic (associated with malaria & EBV)
- Immunodeficiency-related (associated with HIV)
What is the most common chromosomal abnormality in BL?
t(8;14)
All translocations juxtapose MYC with immunogloblin enhancers –> constitutive expression –> uncontrolled proliferation
How is BL characterised cytogenetically?
Absence of genomic complexity - simple karyotype, no translocations other than t(8;14)
What is the prognosis of follicular lymphoma?
Low grade - usually idolent
60-80% progress to DLCBL
What is the most common abnormality in follicular lymphoma?
t(14;18) - BCL2:IGH
What is the prognosis of mantle cell lymphoma?
Intermediate/high grade B cell lymphoma
Often widespread when diagnosed, difficult to cure, high relapse rate
What is the most common abnormality in mantle cell lymphoma?
t(11;14) - CCND1:IGH
What is the prognosis of diffuse large B cell lymphoma?
High grade, acute, aggressive
