Introduction to Cancer Flashcards
What is cancer
A collection of diseases with the shared underlaying features of uncontrolled cell growth and invasion
What is a carcinoma cancer tissue type and give examples
Epithelial
Breast lung and liver
What is a sarcoma cancer tissue type and give examples
Connective tissue
Bones (osteocytes) , muscle, blood vessels
What is a myeloma and leukaemia cancer tissue type and give examples
Bone marrow for both of them
Myeloma: Plasma cells (white blood cells that secrete large volumes of antibody)
Leukaemia: White blood cells, erythrocytes
What is a lymphoma tissue type and give examples
Lymph nodes and glands
Spleen, tonsils, thymus
Which cancer has the highest and lowest survival rate
Non melanoma (highest survival rate)
Melanoma: High to moderate survival rate
Breast and bladder: Moderate survival rate
Lung and pancreas: lowest survival rate
Define Neoplasm
Disorganised growth with net increase in number of dividing cells (similar to tumour swelling)
Define Malignant tumour
Not benign and spread beyond initial site
Define benign tumour
Do not invade surrounding tissue, nor spread
Causes problem when pressing against cell walls
Define Metastasis
Invasion of a tumour to its surrounding tissue and spreads beyond original site
Briefly describe each stage of the cell cycle
- M Phase: Prophase, metaphase, anaphase, telophase
- G1: RNA and protein synthesis
- S: DNA synthesis
- G2: cell growth continues
Explain all steps of M phase
Prophase: chromosome condense, centrosomes assemble
Metaphase: Chromosomes align and attach to spindle
Anaphase: Chromotids pull apart and migrate to poles
Telophase: Chromotids decondense, new nuclear membrane made
Cytokinesis: nuclear membrane decondenses, dividing cytoplasm of mother cell, two daughter cells made
What are the positive regulators of the cell cycle
G1: CDK4/6 (cyclin)
R point (restriction point): can only go through if you have CDK4/6
S phase: E-CDK2, A-CDK2, A-CDC2
G2 Phase: B-CD2
Then you can go to M phase
What are the factors that control cyclin complexes
E2F transcription factors
pRB proteins
One of the hallmarks of cancer is gaining growth factor independence, describe this?
- Cells lose requirement for growth factors to stimulate cell division (gain an oncogene which stimulates cancer)
- Includes:
Growth factor that is normally secreted by surrounding tissue
Mutation in growth factor so it is continually activated
Mutation of components of signalling pathways or transcription factors activated - Gains an oncogene- important in regulation of cell proliferation and lead to growth factors signal always on
What is an oncogene and give an example of the most popular one
- Term given to a mutated or over expressed gene that causes cancer
- Example: Ras- normally in growth signals it leads to signalling events that trigger cell proliferation
- In cancer Ras is constantly on
Give examples of other oncogenes that are not as common
- Bcr-Abl
- myc
- src
- P13 kinase
Give an example of a drug that targets growth factors
Imatinib
A Tyrosine kinase inhibitor that prevents growth factor signals which promote cell proliferation
Give an example of growth factor independence in breast cancer and how to counter it
HER2 (human epidermal growth factor receptor 2): amplified in breast cancer
Counter: Trastuzumab (Herceptin) blocks it
One of the hallmarks of cancer is gaining insensitivity to growth inhibitors, describe this
- Cells lose ability to control abnormal cell proliferation
- This occurs due to alteration in cell cycle regulation which causes loss of TUMOUR SUPPRESSOR GENE
and UPREGULATION of positive cell cycle regulators such as CDC25 or cyclins
How do tumour suppressor genes perform is function and give examples of them
Complete opposite to oncogenes and prevent tumours from forming through detecting DNA damage and mutations, then triggering apoptosis or DNA repair
Examples: pRB, p53 (most commonly mutated in cancer), BRCA
What is the role of p53?
- Acts against lack of nucleotides, UV radiation, ionising radiation, oncogene signalling, hypoxia, blockage of transcription
- Reacts by: cell cycle arrest (stops cell dividing or continue), DNA repair, block of angiogenesis, apoptosis
One of the hallmarks of cancer is proliferation without limit, describe this
- Most cells cannot proliferate indefinitely due to limitation in telomere length (shortens after every proliferation, stick and go through cell death)
- Tumour cells are immortal through production of Telomerase which rebuilds back telomeres
One of the hallmarks of cancer is avoiding apoptosis, describe this?
- Triggered by DNA damage and viral infections
- Gain resistance through pro survival factors such as Bc12
- Loss of function of pro-apoptotic factors like p53
One of the hallmarks of cancer is promoting angiogenesis, describe this
- Tumours stay small until they secure a blood supply
- Provides increased blood supply (nutrients) to tumour to allow continued growth
- Promotes new blood vessel formation through secretion of angiogenic factors
Give examples of angiogenic factors
- Vascular Endothelial Growth Factor (VEGF)
2. Fibroblast Growth Factor (FGF)
One of the hallmarks of cancer is invasion and metastasis, describe this?
- 90% of cancer deaths occur due to cancer spreading to distant sites
- Additional cellular changes is necessary for cancer to overcome containment mechanisms
- Ability to break away from main tumour form metastatic tumours in different areas of body
Pancreas -> Lungs
Breast -> Lungs, liver or bone - Able to do this through decreased cell adhesion molecule expression or protease secretion to break ECM
- Move via lymphatic vessels or blood
What are the different types of gene mutations
- Gene coding regions
- Alterations in transcription or splicing
- Amplifications and deletions of chromosomal regions
- Chromosomal translocations
- Gain and losses of whole chromosomes
- Changes in DNA modification
What causes DNA mutations
UV Free radicals Viruses- hepatitis B/C, T cell leukaemia virus Chemicals Copying and repair errors
What are the three stages of cancer development and describe them
- Initiation: mutation firstly promotes increased proliferation (Carcinogenesis)
- Promotion: additional mutations promote further proliferation (carcinogenesis)
- Tumour progression: Growth and invasion of tumour
Describe the ranks of cancer stages from 1-4?
- Small size not spread
- Moderate size, spread to nodes
- Large size, spread to nodes
- Large size, wide spread
What are the risk factors for cancer
Smoking Inactivity Lack of activity Alcohol lack of fruit and veg red meat Salt INFECTIONS: 18% of all cancers