L25 - Introduction to Lymphomas and Myeloma Flashcards
What is Lymphoma?
It is cancer of the white blood cells (lymphocytes)
It affects mature blood cells, mostly B lymphocytes but also T lymphocytes
What are the main functions of the lymphatic system?
blood filtration and purification
removal of excess fluids from tissues
absorption and transport of lipids
immune system activation
What are lymph nodes and what do they do?
bean shaped structure that is part of the lymphatic system. They filter out substances in the lymphatic fluid and they contain Lymphocytes
What are primary Lymph organs and give examples of where they are located?
Sites where stem cells can divide and become immunocompetant.
- thymus
- bone marrow
What are Secondary Lymph organs and give examples of where they are located?
Sites where most of the immune responses occur
- lymph nodes
- spleen
- payer’s patches
- appendix
- tonsils and adenoids
How does Lymphoma occur and develop
Occurs through a genetic mutation (chromosomal translocation)
It affects mature lymphocytes in different stages, and they start dividing in an uncontrolled manner.
As a result, organs where lymphocytes are numerous increase in size: lymph node enlargement (adenopathy) or spleen enlargement (splenomegaly).
These lymphocytes can spread to other tissues through the lymphatic system. They might infiltrate the bone marrow (in which case it is detectable in blood), and they may cause leukaemias
What are the 2 types of Lymphomas and what are their incidences?
Non-Hodgkin’s Lymphoma = 83%
Hodgkin’s Lymphoma = 17%
What ar the signs and symptoms of Lymphoma?
- swellling of face and neck
- fever
- excessive sweating at night
- lump in neck, armpits or groin
- itchiness
- loss of apeptite
- unexpected weight loss
- breathlessness
- feeling of weakness
How can Lymphoma be diagnosed?
- Lymph node biopsy After this: - NGS - FISH - flow cytometry - immunophenotyping can be used to deduce the type of lymphoma
What method is used to diagnose the stage of Lymphoma and what does each stage represent briefly?
PET is used (positron emission tomography)
stage 1 = localised disease, single lymph node region
stage 2 = 2 or more lymph node regions on same side of diaphragm
stage 3 = 2 or more lymph node regions on either side of the diaphragm
stage 4 = widespread disease, multiple organs - with or without lymph node involvement
Describe the Aetiology of Lymphoma?
It is a mutlifactorial disease:
- malfunctioning of the body’s imune system
- can be due to exposure to certain conditions
Triggers are unknown, however most of lymphomas occur when a B cell develops a mutation in its DNA.
Describe Hodgkin’s Lymphoma and its diagnosis?
- Clonal B-cell malignancy
- presents as non-painful enlarged lymph nodes
- risk factors include family history and Epstein-Barr virus
- diagnosed by performing excisional lymph nose biopsy and seeing reed-sternberg cells, which aren’t present in Non-Hodgkin’s Lymphoma. Reed-sternberg cells are enlarged abnormal lymphocytes that contain more than 1 nucleus.
What is the treatment and prognosis of Hodgkin’s Lymphoma?
TREATMENT:
- chemotherapy and radiotherapy
- stem cell transplant
PROGNOSIS:
- 5 year survival
Describe the presentation, causes and risk factors of Non-Hodgkin’s Lymphoma?
presentation - enlarged Lymph nodes
causes - chromosomal translocations
risk factors - virus infections, like EBV in Burkitt’s Lymphoma
Describe the chromosome translocation in Non-Hodgkin’s Lymphoma?
involves the Ig heavy or light chain loci on chromosome 14.
Ig cells are highly expressed in B-cells, and each Ig gene has a tissue specific enhancer.
In follicular lymphoma:
- the translocations occur between chromosome 14 and 18. BCL-2 gene is an apoptosis inhibitor. When these chromosomes fuse, the enhancer gene on 14 translocates near the BCL-2 gene on 18. As a result BCL-2 gets overexpressed, and prevents apoptosis from occurring
