Unit 3: Cancer Flashcards
What is cancer ?
A group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body
What is cancer characterised by ?
Cell cycle deregulation and uncontrolled proliferation
What are the 5 main types of cancer ?
1) Carcinoma
2) Sarcoma
3) Lymphoma/Leukemia
4) Blastoma
5) Germ cell tumour
How does cancer develop (4) ?
1) Mitogen binds to cell surface receptor
2) This activates an intracellular signalling cascade
3) Increases proteins needed for cell cycle
4) Mutations can happen at any of this stages and this is how this develops
What causes mutations (6) ?
- Free radicals
- Radiation
- UV light
- Viruses
- Bacteria
- Errors in DNA replication
What is Carcinogenesis ?
Formation of a cancer
How many independant mutations are needed for cancer ?
2-12 mutations
What 2 types of cell never enter G0 ?
- Epithelial cells
- Bone marrow stem cells
What is a tumor suppressor gene ?
They encode proteins that stop a cell from proliferating out of control or inducing apoptosis
What is a proto-oncogene ?
A gene that has the potential to cause cancer, usually encode proteins that promote growth, inhibit apoptosis or both
What is an Onco gene ?
A mutant form of proto-oncogene = a cancer cell
What is needed for cancer to occur ?
Mutations in both oncogenes and tumour suppressor genes
What is the relationship between cyclin and cancer ?
Cyclin is over expressed and this is seen in many cancers. This leads to a faster cell cycle so tumours are able to grow faster
What is the function of tumour suppressor genes ?
- Prevent cell cycle progression
- Increase apoptosis
Give an example of a tumour suppressor gene in the cell cycle
Rb
What happens is Rb is mutated ?
- E2F is permanently activated
- The cell can enter S phase without any regulation
- Uncontrolled proliferation
Give 5 properties of cancer cells
- Evade apoptosis
- Overcome replicative senescence
- Uncontrolled proliferation
- Tissue invasion and metastasis
- Induce angiogenesis
What is angiogenesis ?
The growth of new blood vesicles
What is metastasis ?
The spread of cancer from one organ to another not directly connected with it
What is p53 and what role does it play in cancer ?
- It is a component of the G1 checkpoint
- DNA damage increases p53 which halts cell cycle until repaired and induces apoptosis
- Means kills mutated cells
What is the most common type of cancer in dogs ?
Osteosarcomas = primary bone cancer
