Cancer Flashcards
What cell types does cancer largely occur in?
somatic cells
Is cancer a disease?
no
rather, it is a family of related complex diseases
this is why there will never be any one cure for cancer
two fundamental properties of cancer
- unregulated cell proliferation
2. metastatic spread
How does cancer spread?
through the bloodstream
How does cancer occur?
the accumulation of many mutations
very rarely occurs from a single mutation
How can you determine if cancer in two different locations arose independently from one another or are from the same original tumor?
- compare base sequences in both areas
2. look for similar chromosomal irregularities in karyotype
Tasmanian devil facial tumor disease (DFTD) case
DFTD is a rare transmissible form of cancer
Due to eating together and violently clawing prey, tasmanian devils can transfer cancer through blood on their face
they also have little genetic diversity which gives rise to this
Mutation error rate
10^-6 mutations per gene in each division
How many mutations might a person have per gene in a lifetime?
10^10
Why does the risk of cancer increase with age?
acquire more mutations as more divisions take place and the risk of cancer increases
What happens if cyclins are never degraded?
CDK proteins will always be on and cell cycle will progress without control
this can lead to cancer
Retinoblastoma (RB) checkpoint protein
ensures that the cell passes from G1 to S only when ready
tumor supressor protein
what happens when RB is on?
the cell does not pass from G1 to S
how do you turn RB off? what happens when RB is turned off?
RB is phosphorylated to turn off by cyclin-CDK complexes
when RB is turned off, the cell is free to move into the S phase
How does RB work?
binds to transcription factor (E2F) that promotes gene expression and prevents it from transcribing certain genes
when RB is not bound to E2F, E2F allows certain genes to be expressed that further the cell from G1 to S
