Nature of cancer Flashcards
5 examples of the hallmarks of cancer
sustaining proliferative signalling evading growth suppressors avoiding immune destruction* inducing angiogenesis resisting cell death genome instability and mutation* enabling replicative immortality activating invasion and metastasis
Why is cancer an evolutionary disease?
because cells are constantly competing and trying to survive- basis of natural selection and evolution
Which experiment/study showed that environment had a party to play in cancer? What was the key conclusion?
Looked at the migration of Japanese people to Hawaii
japan- has a profile of higher rates of stomach cancer
european originated people- profile of higher rates of prostate and breast cancer
japanase hawaiian people- had a profile consistent with caucasians-
KEY conclusion= environment has a significant impact on the type of cancer were likely to develop
What is the relationship between log age and log incidence of cancer?
Linear
What increases the probability of a change associated with cancer?
Age
What does LogP(T)= nLogA + constant - give us?
A slope with the number of changes needed for cancer to develop- which is approximately 6
What observation in families led to the recognition that tumour suppressor genes exist?
families being susceptible to particular cancers
retinoblastoma, wilms tumour, adenomatous polyposis coli, hereditary breast cancer
all inherited in a mendelian fashion- implied genetic control of cancer
therefore there must be genes keeping cells in check
3 historical figures that were key in producing evidence of influences contributing to cancer?
Percival Pott- chimney sweeps and scrotal cancer
John Hill- snuff and nasopharyngeal cancer
Richard Doll- ‘father of cancer epidemiology’- smoking and lung cancer
When was cancer first experimentally induced and what was the experiment?
1915- benzopyrene was extracted from coal tar and rubbed on rabbits ears- rabbits developed carcinomas of the ears
Why was the cause of cancer a confusing topic for a long time?
chemicals were shown to cause cancer
newly developed X rays- if you irradiated someone alot- causes cancer
viruses (RSV) were also known to cause cancer
what linked all 3?!
What theory linked x-rays, chemicals, viruses and cancer together?
The mutagenesis theory for cancer
What are the 2 mouse models of cancer?
- Onco mouse- genetically engineer a mouse- cause a genetic change and observe endogenous cancer forming
- Xenograft mouse - graft cancerous human cells into an immunocompromised mouse- mouse will develop tumours from these cells
What are xenotransplant mice commonly used in?
Preclinical trials
when testing a new drug which is effective for a particular cancer
produce the relevant xenograft mouse and then treat the mouse with the drug
look at the number of tumours and the rate of induction
Drawbacks to the oncomouse
The cancer has mouse characteristics rather than human
issues with the time of onset
mice dont live as long as humans- cannot see the full nature and behaviour of primary and metastatic tumours
Drawbacks to the xenograft model of cancer
time of onset is artifical so its not perfect
problem with nature and behaviour of primary and metastatic tumours
the mice are immunocompromised- so cannot see the role the immune system has in the development of the cancer
