(25) Cancer Biology Flashcards
1
Q
(Cancer Biology - Tumor Immunology)
- Tumor simply means what?
- but is equated with what?
- which means what?
A
- swelling
- neoplasm
- new growth occuring in an excessive or unregulated manner
2
Q
(Two types of neoplasms)
- Which type invade into adjacent tissue layers and/or deposit in distal tissues via the circulatory or lymphatic systems?
- Which type are noninvasive?
A
- malignant tumors
- benign
3
Q
(Cancers can arise from almost any tissue cell in body)
- malignant tumors of mesenchymal tissues (fibroblasts, muscle cells, and fat cells)
- Malignant tumors of epithelial cells
- neoplastic growth lymphocytes that often originate in lymph nodes
- a cancer of the blood or bone marrow leukocytes
A
- Sarcoma
- carcinoma
- lymphoma
- leukemia (lymphoblastic or lymphocytic leukemias are myeloid or myelogenous leukemias)
4
Q
(Cancer Development)
- Typically the result of a multi-step process - called what or what?
(1. Tumor initiation)
2-4. Caused by what three things?
- What type of cells are induced?
(2. Tumor Promotion) - Results in growth of what?
- Agents that cause what can be promoters?
(3. Tumor Progression) - Induction of what?
A
- carcinogenesis or oncogenesis
- Unrepaired alterations in cellular DNA [chemical (nitrosamines)]
- physical (UV rays)
- genetic mutations to cellular DNA (genetic/somatic)
- preneoplastic
- neoplastic cells
- Agents that cause mitogenesis (cell division) - (eg saccharin, estrogen, phorbol esters, cytokines)
- invasive growth
5
Q
He says this is for our information - but learn it
A
6
Q
(Tumor Immunology - Immunosurveillance)
- What is the ability of the immune system to detect tumor cells and destroy them?
- Do tumors show evidence of immunological control?
3-8 - What are five ways that tumors avoid immune system?
A
- Tumor immunosurveillance
2. Most tumors show little evidnce of immunological control
- low immunogenecity (doesn’t express molecules to be bound to)
- tumor treated as self-antigen
- antigenic modulation (down-regulation of antigens)
- secrete cytokines (TGF-B) to inhibit T cells
- create physical barrier (tumor-induced privileged site)
7
Q
(Tumor Antigens)
- What are unique or altered proteins and sugars (glycans) expressed by tumor cells
- What are proteins derived from mutated, silent, or viral genes expressed by tumor cells? What does this result in? What can these antigens invoke?
A
- tumor antigens
- tumor-specific antigens; presentation of essentially foreign antigens by MHC; a T cell or antibody response because they are foreign to the immune system
8
Q
(Tumor antigens - cont)
(Products of mutated genes)
- What type of gene (when dysregulated), makes a protein product that participates in the onset and development of cancer?
- What is a normal gene that can become an oncogene due to mutations or increased expression? What do these encode for? When they are altered they participate in what?
(Products of Viral Genes)
- Viruses can incorporate what into host cells?
- These can make the cells what?
- Their protein products can also serve as what?
A
- oncogene
- proto-oncogene; encode for proteins that help to regulate the cell growth and differentiation; onset and development of cancer
- genes and genetic material
- cancerous
- tumor antigens recognized by the immune system
9
Q
(Tumor Antigens)
- What are normal cellular antigens expressed by tumors in an atypical fashion? These antigens are typically less efficient at what? Can be beneficial for what?
- What are proteins that are typically present only during fetal development but are found in adults with certain kinds of cancer?
- What can occur by the abnormal addition of glycan strutures to cell surface proteins and lipids?
A
- tumor-associated antigens; less effecint at invoking an immune response since they may not be perceived as foreign; dianostics/therapeutics
-
oncofetal antigens
(fyi) an example of an oncofetal antigen is alpha-fetoprotein (AFP), a predominant serum protein in the fetus produced by hepatocytes, which disappears upon birth. In some dogs with hepatocellular carcinoma, serum levels of AFP will increase - altered glycosylation of cell surface lipids
10
Q
(Immunosurveillance)
- These cells play a well established role in killing tumor cells. Are particularly effective in immunosurvillance for what?
- These are generally not cytotoxic, but can play a role in anti-tumor responses. By providing what that do what?
- These cells attach to and kill antibody coated tumor. By their what?
- B cells - antibodies attach to cell surface tumor antigens and activate what?
- Specialized lymphocytes (but not T or B) thatn do not express antigen specific receptors (ie no T or B cell receptor)
A
- Cytotoxic T lymphocytes (CD8); viral-induced tumors
- Helper-T lymphocytes (CD4); providing cytokines that stimulate CD8 T cells, B cells, and macrophages
- Macrophages and neutrophils; Fc receptors
- activate complement or Fc receptor expressing leukocytes
- Natural killer cells
11
Q
(Natural Killer Cells)
- Arise from what lineage?
- innate or adaptive?
A
- lymphoid (therefore a lymphocyte)
- innate
12
Q
(NK CELLS)
- How are NK cells similar to CD8 T cells?
- How are NK cells different from CD8 T cells?
- What enzymes do both of these release to kill stuff?
A
- both cytotoxic lymphocytes and recognize class 1 MHC on tumor cells
- Don’t express T cell receptor (TCR) and kill target cells when they _don’_t recognize MHC
- perforin and granzyme release
13
Q
(NK cells)
learn this slide
A
14
Q
(NK CELLS)
(Antibody-Dependent Cell Cytotoxicity (ADCC))
- What is an Fc receptor expressed by NK cells?
- What does it bind to acomplish what?
- What signals the NK cell to kill the target cell?
A
- CD16 (FcyRIII)
- binds antibodies attached to tumor cells and mediates their killing
- cross-linking of Fc receptors (target cells die by apoptosis)
15
Q
(Therapies)
- What are three standard therapies?
A
- surgical, chemotherapy, and radiation
