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26 Cards in this Set
- Front
- Back
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What are common genetic defects in cancer? |
Proto-oncognes act improperly, apoptosis genes defective as well as tumour suppressor genes |
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What is neoplastic tissue? |
Cells grow uncontrollably |
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Difference between benign and metastatic tissue? |
Both grow uncontrollably but benign is not capable of spreading (metastasizing) and growing uncontrollably indefinitely |
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How can a virus cause cancer? |
Virus integrates into the host cell DNA and cause mutations that can create defects in tumour suppressor genes etc. |
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What virus is activated by HIV and how can it cause cancer? |
HHV-8 is activated when HIV infects the host and suppresses the immune system (with a suppressed immune system the virus can propagate again) When the virus begins to propagate it can induce mutations that may cause cancer |
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What lymphocyte is responsible for recognizing unique tumour associated antigens? |
CD8 (killer) T-cells |
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What are tumour specific antigens? |
Antigens that either arise through mutations to normal genes or from completely foreign genes |
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What is a tumour associated antigen and how does it differ from a TSA? |
These are antigens that have much greater expression in tumour cells compared to native cells, but are not exclusively found in tumours |
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What is another form of TAA? |
Antigens that expressed in a similar quantity to what is found in native cells, but they are expressed ubiquitously throughout the lifecycle rather than at specific points of development (i.e. embryonic) |
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Mutations in what innate immune cells lead to a greater susceptibility to cancer? |
Mutations to NK cells increase risk of certain types of cancers |
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How do mutations to adaptive immune cells result in increased risk of cancer? |
Certain T-cells are tumour infiltrating and therefore lose of them increases risk of cancer Similarly, B-cells can produce antibodies against TSAs and therefore depletion of B-cells increases risk of developing cancer |
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What are the most important cytokines for preventing cancer cell proliferation and survival? |
IFNs, TNF-a, and IL-12 because it activates Th1 cells that produce primarily IFN |
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What is the elimination phase of tumour immunology? |
It is when the immune system responds to the tumour cells as if they are pathogens by recognizing either TSAs or TAAs |
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What happens as the elimination phase progresses? |
Begins with recruitment of innate immune cells and anti-tumour cytokine production and culminates with the arrival of T-cells |
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What is the equilibrium phase? |
It is when tumour cells have survived the immune response generated against them and mutated ones continue to grow |
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What is the escape phase? |
The resistant cells that survived the immune response continue growing and may eventually metastasize |
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How is inflammation correlated with cancer? |
Inflammation increases stress signals in cells which can induce mutations, additionally pro-inflammatory cytokines can stimulate propagation Finally inflammation is often pro-angiogenic leading to increased blood vessel synthesis which provides additional passageways for tumour cell metastasis |
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How do tumours act to suppress the immune system? |
1. Activate T-reg cells 2. Recruit MDSCs 3. Secrete anti-inflammatory cytokines (TGF-B and IL-10 |
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How do tumour cells evade the immune system? |
1. Reduced MHC expression 2. Poor Co-stimulatory ligand expression |
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How does the tumours actions help it to evade the immune system |
Reduced MHC and fewer co-stimulatory ligands mean that T-cells will not be activated against the cancer cells and since they are not capable of being activated can become anergic |
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How do the tumour cells reduce expression of MHC? |
They have mutations to their TAP and B2 microblogulin which prevent the production of MHC class 1 to activate killer T cells |
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How does cancer immunotherapy work? |
Cells are removed from a cancer patient either from the site of the tumour or the blood and the T cells are allowed to grow ex vivo with supplementation of the proper cytokines |
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Why is growing T-cells ex vivo against tumour more successful than in vivo? |
In Vivo there the tumour cell suppress their growth too much and do not express the peptide in a way that enables activation (therefore often get anergy) |
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What is the most important cytokine for growing T cells? |
IL-2 |
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What is DC based therapy? |
Cancer immunotherapy that relies upon dendritic cells Either the dendritic cells are taken from the patient and pulsed with tumour antigens or they are transfected with tumour antigen cDNA and vaccinated back into the patient to create anti-tumour T cells |
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What are the novel methods of cancer immunotherapy? |
mAb (biologic agents) that target specific proteins involved in signalling pathways such as HER2 (important in certain breast cancers) Immunotherapies that create an immune response against the tumour cells |
