Term
| What are the leading causes of cancer-related death? |
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Definition
1) Lung
2) Stomach
3) Colon
4) Liver
5) Breast |
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Term
| What is the :cancer immunoediting" hypothesis? |
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Definition
Elimination (cancer immunosurveillance)
Equilibrium (immune-mediated latency after partial destruction)
Escape (final outgrowth) |
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Term
True or False
Many tumors are immune reactive |
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Definition
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Term
| What is the immunesurveillance hypothesis? |
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Definition
Sential thymus-dependent cells of the body (T-cells) constantly survey host tissues for nascently transformed cells.
Cancer develops, when cells escape surveillance. |
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Term
| What is the difference between normal differentiation antigens, tumor-specific antigens and tumor-associated antigens? |
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Definition
1) Normal- seen in normal cell proliferation (MART-1/Melan-A, gp100, tyrosinase, TRP-1)
2) TAA- relatively restricted to tumors (tumor-inducing viruses)
TSA- unique to tumors (MAGE, BAGE, CAGE) |
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Term
| What are "Onco-fetal" antigens and how might they contribute to cancer? |
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Definition
Antigens should only be found early in life, but pop of later in cases of cancer.
AFP (secreted)
CEA (secreted and membrane-bound) |
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Term
| What are the primary immune effectors in anti-tumor immune responses? |
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Definition
1) T-cell for direct recognition of intracellular TAA bound to MHC-1 leading to cytolysis (sometimes requires B-cel Antibody-binding-ADCC)
2) NK cell for ADCC (stimulated by IL-15, INF-y and IL-2) and tumor cells lacking MHC-1
3) APCs present antigens to CTLs
4) Cytokines (IL-12, IL-2 (leads to LAK production), TNF-a, IFN |
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Term
| What is the difference between Humoral and Cell-mediated tumor suppression in terms of the types of cancer that they regulate? |
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Definition
Humoral- only seen in leukemias and lymphomas in vivo
Cell-mediated- see in many animal tumors |
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Term
| What are the known mechanisms by which tumors escape immunosurveillance? |
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Definition
SHORT
1) Antigen immunogenicity, shedding and variation
2) MHC expression
3) Enhancing antibodies
4) Tregs and MDSC release of TGF-b and IL-10
Explanation
1) Tumors may not express neo-antigens that are immunogenic (or absence of co-stimulators)
2) Poor MHC expression
3) Antigen shedding and conformational shifting (antigenic variation)
4) Enhancing antibodies may bind to tumor cells and protect them from T cells
5) TGF-B and IL-10 release and cytokines that induce their own proliferation (myeloma and HTLV-1 T cell leukemia)
6) Tumor growth may lead to myeloid-derived suppressor cells (MDSC) and Tregs, which suppress CTLs and NKs |
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