Signal Transduction and Oncogenesis Flashcards
What is Cancer?
A group of heterogeneous pathologic states in which cells multiply abnormally and invade surrounding tissues
How many types of human cancers are there?
More than 200
What are the SIX features of cancer cells?
- Grow out of control
- Interfere with normal tissue
- Suffer loss of regulatory system function
- Display clonality
- Display anchorage independence
- De-differentiation
What are the FOUR major groups of human cancers?
- Carcinoma
- Sarcoma
- Leukaemias
- Lymphomas
What is Carcinoma?
Cancer of epithelial cells
What is Sarcoma?
Cancer of connective tissue
What are Leukaemias?
- A class of sarcoma
- Grow as individual cells in the blood or bone marrow
What are Lymphomas?
- A class of malignant sarcoma
- Solid tumours of lymphocytes and plasma cells
How are cancers classified?
- Site of origin
- Cell type
- Named after discoverer
What are the FOUR general steps in tumour staging?
- Formation
- Invasion of surrounding tissues
- Entry of cancer cells into circulation
- Metastasis
What are the TWO types of tumour?
- Benign
- Malignant
Which tumour type is able to metastasize?
Malignant
What are Invadopodia?
Finger-like plasma membrane protusions formed by cancer cells during migration
What are Oncogenes?
Genes that encode oncoproteins that promote cancer
What is a Proto-Oncogene?
Normal version of a gene involved in control of cell growth / division
How do Proto-Oncogenes become Oncogenes?
Through mutation (point, insertion, or deletion)
What is an example of a sis oncoprotein?
Platelet Derived Growth Factor (PDGF)
What is sis oncogene?
First oncogene to be identified as having homology to a known cellular gene
What cancers are a result of oncogenic Growth Factors?
Meningiomas and some skin neoplasms
When do RTKs become oncogenic?
If active even in the absence of a ligand
What is VEGF?
Growth factor important in angiogenesis (formation of blood vessels by tumour)
What cancers are a result of oncogenic RTKs?
Breast & Colon
What is the function of p53?
- Senses DNA damage (DNA damage)
- Halts cells from proliferating
- Causes cells to undergo apoptosis
Which protein is p53 normally sequestered to?
MDM2
How does p53 sense DNA damage?
Through another protein called ATM that signals p53 by phosphorylation
What can cause inactivation or mutations in p53?
Chemical carcinogens
* cigarette smoke inactivates p53
* asbestos causes mutations in p53
How does a tumour inactivate p53?
Increasing MDM2 levels
Where do p53 mutations generally occur?
DNA binding domain
