The Basic Science Of Oncology Flashcards
What causes cancer?
1/3= chemical carcinogens, radiation exposure, heritable genetics/ epigenetic, viruses
2/3= mistake in replication
Drivers (genetic mutations)
Confer a selective growth advantage
Time to 2nd driver mutation faster than 1st
Gatekeeper and caretaker mutations
40-60 total
Passengers (genetic mutations)
Do not alter fitness but occurs in a cell coincidentally or subsequently acquired a driver mutation
Initiation
Reactive with DNA, irreversible damage fixed
Damage to genes
Promotion
Promote proliferation, large number of daughter cells containing the mutation
No effect if not previously treated with an initiator
Progression
Stepwise transformation to malignancy
What are the hallmarks of cancer
Sustaining proliferative signaling
Evading growth suppressors
Avoiding immune destruction
Enabling replicative immortality
Tumor- promoting inflammation
Activating invasion & metastasis
Inducing angiogenesis
Genome instability & mutation
Resisting cell death
Deregulating cellular energetics
Cancer is considered a genetic dz, but is it heritable?
Yes
How many alleles must be altered in oncogenes for cancer to develop? Tumor suppressor genes?
Oncogenes- 1 hit
Tumor suppressor genes- 2 hits
What are microRNAs (miRs)?
Family of molecules that helps cells control the kinds and amounts of proteins they make
Help control gene expression
What are telomeres? Telomerase?
Structures made from DNA sequences and proteins found at the end of chromosomes
An enzyme in cells that helps keep them alive by adding DNA to telomeres
Is telomerase increased or decreased in tumors?
Increased
How big can tumors grow before a blood supply is necessary for further growth?
1 mm^3
What nutrient do tumor cells preferentially use for energy?
Glucose
What is the tumor stem cell debate?
- Mutation of stem cells (few)
- Somatic cells acquire stem cell characteristics (small percentage of tumor cells, unlimited replicative potential, recapitulate tumor, resistant to therapy)
