26 - Introduction to Lymphoma Flashcards
what is lymphoma? which cells does it affect?
cancer affecting the lymph system - especially white blood cells/ lymphocytes
mutations primary affects B cells, also T cells (terminally differentiated white cells), can affect blast cells, but doesn’t affect haemopoietic stem cells
what is the lymphatic system, and how does it function?
lymphatic system = a complementary circulatory system that carries immune cells throughout the body, follows a path similar to blood circulation
- helps immune surveillance
- allows immune cells to enter the blood and detect invading pathogens
characteristic of lymphoma?
heterogenous group of diseases = often caused by specific genetic mutations and chromosomal translocations - these can affect the activity of tumour suppressor genes and oncogenes
the accumulation of mutations over time makes it more prevalent in the elderly
what are lymph nodes?
lymph nodes = small structures throughout the lymphatic system, contain high concentrations of lymph and immune cells
list and describe some functions of lymph nodes
purify/ filter blood
- capillary blood passes through lymph nodes
remove excess fluid from tissues
- the activation of immune cells increases the volume of interstitial fluid between tissues, which causes swelling = this needs to be reduced following infection
- fluid drains into lymph system
involved in absorption and transportation of lipids
activate the immune system
- nodes contain a high conc of immune cells
- when pathogens enter the lymphatic system, their antigens are presented to immune cells = triggers an immune response
- leads to antibody production and proliferation of cytotoxic T cells
what are primary lymphoid organs, and what is their function?
sites where immune cells develop and mature - bone marrow and thymus gland
hematopoietic stem cells differentiate into immune cell lineages in bone marrow - B cells develop, mature and become immunocompetent
immature T cells migrate from bone marrow to thymus for further maturation and selection to become functional T cells
what is the role of secondary lymphoid organs in the immune system?
sites where most immune responses occur once immune cells have matured - e.g. lymph nodes, spleen, tonsils, and mucosa-associated lymphoid tissues
immune cells circulate through the blood and lymphatics, encounter foreign antigens, migrate to secondary lymphoid organs to interact with antigen-presenting cells and mount an immune response
their higher conc of immune cells increases the chance of encountering and responding to pathogens
how do primary and secondary lymphoid organs differ in their function?
primary lymphoid organs = responsible for the development and maturation of immune cells
secondary lymphoid organs = sites where immune responses occur after immune cells have matured
what is immunocompetent?
capable of recognising and responding to antigens
describe how lymphoma manifest, grows and spreads
stages: accumulation of mutations affecting lymphocytes in different maturation stages, leads to uncontrolled division and tumour formation, angiogenesis, increased organ size, mutated lymphocytes spread to other tissues/ organs through the lymph and circulatory system, lymphocyte infiltration may occur at bone marrow and more distant organs (metastasis)
- accumulation of mutations in terminally differentiated B & T cells as well as blast cells can activate oncogenes and deactivate tumour suppressor genes = leads to uncontrolled division of lymphocytes
- tumours form - increases size of lymph nodes (adenomegaly) and other lymphoid organs like the spleen (splenomegaly)
- angiogenesis, increased growth of lymphoma tumour
- mutated lymphocytes and tumour cells can spread throughout the body by the lymphatic system or by breaking through the endothelial layer into the blood system - tend to travel to closest organ/ tissue, can travel to distant organs
5; lymphoma infiltration into bone marrow and other organs = metastasis
describe the main classifications of lymphomas
- Hodgkin’s lymphoma
- typically arises from B cells, characterised by presence of Reed- Sternberg cells
- divided into classical and nodular
- less common than non-Hodgkin’s - non-Hodgkin’s lymphoma
- don’t contain Reed-Sternberg cells, contains a diverse group of lymphomas and subgroups involving B, T and NK cells
- more common than Hodgkin’s
describe the presentation for lymphoma
similar to having a flu/ being sick for an extended period of time
fever
swelling of the face and neck = lumps on neck, armpits or groin from growth of lymph nodes
excessive sweating
itchiness
unexpected weight loss and loss of appetite
feeling weak, breathlessness, tiredness/ fatigue
describe the diagnosis procedure for lymphoma
- lymph node biopsy
- sample taken from armpits - needle inserted into swollen lymph node - histological analysis & immunophenotyping
- staining for nuclei and various cell types
- observing any morphological & phenotypic irregularities/ differences expected in cancerous cells
- observing immune cells for abnormal structure and function - sequencing - FISH, NGS, flow cytometry
- FISH = detects genetic abnormalities or chromosomal rearrangements associated with types of lymphoma
- NGS = sequencing, identifying genetic abnormalities
- flow cytometry = helps classify lymphoma subtypes by looking at surface markers - staging through PET scans
what are the stages of lymphoma?
4 stages:
stage 1 - localised cancer of a lymph node to a single region in the body
stage 2 - cancer affects 2 or more lymph nodes on the same side of the diaphragm
stage 3 - affecting lymph node regions on both sides of the diaphragm
stage 4 -cancer has spread beyond lymph nodes to other tissues/ organs = metastasis
what are some factors contributing to the aetiology of lymphoma?
multifactorial disorder - various factors play a role
- malfunction of the immune system
- viral infections - e.g. EBV , HPV
- genetic mutations
