Intro To Cancer Biology Flashcards
What are cancer cells
Normal cells that have gotten genetic mutations that let them survive and proliferate independently from the normal cell cycle signals
What is metastasis
The spread of cancer from the primary site (where it started)
What is a characteristic of a abnormal cell
A larger size of nucleus
What are the three main groups of tumours
Sarcomas
Leukemias and lymphomas
Carcinomas
What are sarcomas
Rare, less than 2%
Solid tumours made of connective tissues
Like bone, cartilage and fibrous tissues
What are Leukemias and lymphomas
8% of cancer
Come from blood forming cells (leukaemia)
And from immune system cells (lymphomas)
What are carcinomas
90% of cancers
Come from epithelial cells
What are the 4 causes of cancer
Exposure to carcinogenic chemicals
Ionizing radiation
Viruses (that alter the genome, papilloma virus)
UV light
What is an example of a virus and what is its characteristics
The human papilloma virus
Found in 90% of cervical cancers
But most women with the infection don’t develop the cancer
How can viruses cause cancer
They are able to transform cells from normal to cancerous
This is because the virus can pick up cancer causing genes whose protien products stop the cells growth regulating activities
Is cancer genetic or inherited
Genetic (changes to dna)
How do the mutations that cause cancer happen
Due to somatic (not in germ cells) mutations in specific genes
How do inherited mutations affect cancer risk
Inherited mutations like mutations in BRCA1 and BRCA2 genes
This increases the risk of breast and ovarian cancer
But this is rare (5%)
BRCA1 and BRCA2 help with what
DNA repair
If mutated the cell cant repair dna and mutation can accumulate and risk of cancer increases
In what way does cancer affect the shape of chromosome
Chromosomes could duplicate, and have other parts of chromosomes translocated onto it
Where would mis-segregations of chromosomes occur
During mitosis
What are the hallmarks of cancer
Sustaining proliferative signalling (making RAS growth factor independent, ex RAS)
Evading growth suppressors
Activating invasion and metastasis (cancer migrating)
Allowing replicative immortality (dividing infinitely)
Inducing angiogenesis (Forming new blood vessels to take away the waste of the cancer tumor)
Resisting cell death (no apoptosis)
What is contact inhibition
The inhibition/stopping of cell division in normal cells when they contact or a neighbouring cell
It stops the cells motility and proliferation since they can’t grow over top of each other
This lead to them making a monolayer
What is special about tumor cells in regard to contact inhibition
The tumor cells have lost their contact inhibition
So they begin to grow on top of each other after the first layer is formed
Describe how serum in cell cultures can affect normal and cancer cells
Cancer cells eventually become growth factor independent
Serum has growth factors
So when there is no serum, normal cells would not grow as much
When there is serum , normal cells grow then level out at some point bc of contact inhibition
cancer cells with serum grow, cancer cells without serum also grow at same rate
Basically cancer cells don’t need serum to grow
What is anchorage independence
Cancer cells can grow without an ECM since the don’t need adhesion
They can grow in agar which doesn’t have a ECM
But normal cells need ECM to grow since the need interaction with their integrin
What can cancer cells do since the have anchorage indoependencd
Since the don’t need to adhere to the ECM , they are able to freely float through the body and not die
What are ways that cancer progresses
It’s caused by mutations in tumor suppressor genes (deactivating) and proto oncogenes (activating genes that promote cell growth
It can progress through:
loss of control over cell proliferation
Loss of adhesion to neighbouring cells and the basement membrane
Use of matrix metalloproteinases to digest the basement membrane
Invasion into surrounding tissue and blood stream or lymph system
What is involved in loss of adhesion in cancer cells
They lose their E-cadherins
They lose their integrin (not required for survival anymore, can still have and use them but not needed for survival
