Cell Reproduction Flashcards
Who is most likely to get cancer?
Old males
Why is cancer becoming more popular?
It’s a disease of the aging population
What cancer has the higher number of deaths?
Lung then breast and prostate
What is carcinoma?
Cancer arising from epithelial cells- about 80-90% of all cancers
What is sarcoma?
Cancer of connective and supportive tissue- about 1% of cancers
What is myeloma?
Cancer of the plasma cels of bone marrow- antibody producing cells
What is lymphoma?
Solid tumours of lymphatic system
What is leukaemia?
Blood cancer- precursor blood cells in bone marrow
What are two important qualities in normal cells in culture ?
Anchorage dependant growth- no attachment no growth
Density dependant growth- stop growing when confluent
What are two important qualities in cancerous cells in culture?
No anchorage dependant
Not density dependant- growth not controlled by other cells
Do cancerous cells have a limited amount of divisions?
No they can maintain telomere length
Do cancerous cells always need mitogens and growth factors to grow?
No
How can cancer cells promote growth?
Over produce growth factors
What are the stages of cancer?
Initiation Clonal expansion Primary tumour Secondary mutations Malignancy Invasion Metastasis
How many mutations does it take to overcome normal cell programming?
Multiple
What happens in initiation?
Single cell undergoes a single mutation - confers a growth advantage which causes it to lose some of its growth control
What happens in clonal expansion?
Proliferation begins - mutated cell divides quicker than surrounding cells to form a cluster of ‘clones’ - disease is monoclonal
What is primary tumour?
The cancer remains in situ (i.e. not moved from site of original mutation). Tumour benign - not invaded surrounding tissues - surgery possible
What is secondary mutation?
Secondary mutations provide a new phenotype with a selective advantage
What is malignant cancer?
Following the secondary mutation the cells lose contacts with their neighbours - become invasive - secrete proteases to breakdown the extracellular matrix holding cells in place - risk of metastasis
What is invasion of lymph?
First stages of metastasis - cancer cells have low adherence - easy to break off main tumour and enter vessels
What is metastatic tumour?
Colonisation of a second site. Cell from original tumour in lung has now entered a vessel and emerged at the other end to form a new tumour in another organ
What are characteristics of malignant tumours?
Excessive proliferation Unusual number of chromosomes Deranged metabolism Reduced attachment to neighbouring cells Invasive phenotype Proliferate to other parts of the body (metastasis)
What are examples of carcinogens?
Cigarette smoke
UV radiation
Viruses
Is cancer genetic?
Partly e.g. retinoblastoma
Mutations of which proteins cause cancer?
proto-oncogene and tumour supressor gene
What is an oncogene?
Mutated proto oncogene
How do proto oncogenes become oncognees?
New promoter means more protein
Increased gene replication
Mutation of promoter
Change of protein itself
How were oncogenes discovered?
Extract DNA from human tumour cell Transfected into a mouse Extract mouse genomic DNA from cells containing human oncogene Add to plate of bacteria Blot of filter paper Found to code for signalling pathways
What happens when Ras becomes mutated?
It’s always switched on
