L1 Flashcards
what is meant by monoclonal in terms of tumours?
Monoclonal means a population of cells which all derive by direct descent form a common ancestral cell.
e.g. tumours/cancer derives form a single cell
(although may appear to be a hetegeneous population due to aquired mutations in the population)
Give the 8 hallmarks of cancer
- Angiogenesis
- Avoid cell death/apoptosis
- Maintain proliferative signalling ( ignore anti-proliferative signalling)
- Avoid immune destruction
- Genome instability and mutations
- Evade growth suppressors
- Activate invasion and metastasis
- Enable replicative immortality (avoid shortening of telomeres)
what is cancer thought to be a consequence of?
Micro-evolution - a small number of mutations are enough to cause a cancer phenotype
How many people likely to be diagnosed with cancer in UK?
1 in 2 individuals
what is the major risk factor of cancer?
AGE
exponential increase between age and rate of cancer per 100,000
what creates a linear relationship?
log age vs log annual incidence
LogP(T) = nlogA + constant
(number of mutations increases with age?)
slope is 6 - (n) number of mutations required to induce cancer phenotype?
What was concluded from study which looked at japanese people who migrated from Japan to Hawaii?
- Major cancer risk is environmental
- environment is major driver for cancer
- Japanese people who lived in Hawaii has similar cancer prolife to Caucasion people (who lived in hawaii)
- no longer represent japanese cancer profile
What cancer is high in Japan and why?
Stomach cancer in Japan is high - due to high amount of sulphites in diet?
(japanese people who live in hawaii do not have high incidence of stomach cancer)
which cancers are particularly susceptible to some families? (risk acquired genetically?)
- retinoblastoma
- Wilms tumour
- adenomatous polyposis coli
- hereditory BC
(implies existence of tumour suppressor genes - LOF=cancer phenotype)
what is the link between smoking and lung cancer?
number of cigarettes smokes increases the incidence of lung cancer in countries that smoke more cigarettes.
- 20 year lag time between smoking and lung cancer
what happened experimentally in cancer in 1915?
Cancer (Carcinomas) could be induced on rabbits by using coal/ benzoApyrene
- was conc and time dependent
- by yamagiwa
what were the 3 origins of cancer in the 1950s?
- chemical - coal/ benzopyrene
- viral - Rous sarcoma virus
- physical - x-rays/ radiation
(mutagenesis theory)
what was the test used to test for mutagenicity?
the Ames Test
- homogenised liver of rat (or other species) - release enzymes to activate chemical to its mutagenic form.
- liver mixed with test compound (conversion to chemically activated state)
- mixture applied to dish of mutant salmonella bacteria which require histidine to grow in culture
- culture bacteria in culture with no histidine - if can grow know bacteria have acquired a mutation to grow independently of histidine.
- count cells which have acquired mutation
(although not all carcinogens are mutagenic)
what experimental model was used in 1986 and by whom?
The oncomouse
- cancer induced in mice
- mouse cancer model
- Leder and Stewart
what is the xenograft model of cancer?
Immunodeficient (SCID) mice which are induced to have human cancers - inject human cells
