What is cancer Flashcards
Define malignancy (2)
Can spread to other sitesand penetrate the basement membrane
what is cancer
unregulated growth of malignant tumours
INVASION!!!
what don’t cancer cells need in order to survive?
growth signals
what is dedifferentiation
cell differentiates into a normal cell, but then acquires mutations so becomes dedifferentiated (doesn’t look or behave like original cell type)
what do cancer cells not do?
die
which gene is the guardian of the genome and why
P53 transcription factor increases expression of p21 (cyclin dependent kinase inhibitors)
describe some features of normal cells behaviour
controlled growth, die by apoptosis, repair DNA mutations, stay within the tissue
describe some features of cancer cell behavious
uncontrolled, do not die, DNA mjutations proliferate, migrate and invade other tissues and the bloodstream
what do proto-oncogenes normally do?
regulate the rate of cell division and cell growth
what does a mutation in a proto-oncogene result in
GAIN OF FUNCTION - turns into oncogene
what is the definition of a dominantly activated gene?
one that gains functiuon with mutations
give some examples of types of oncogenes with examples
growth factors
growth factor receptors EGFR, HER2, VEGFR
kinases or other intracellular signalling proteins MAPK IP3
transcription factors c-myc
which genes regulate the checkpoints in the cell cycle
TSGs
what do TSGs do
induce apoptosis, DNA repair, stop cells at the checjpoints
What is recessive action
eg when TSGs are activated, less happens
how many copies of TSG need to be mutated for a loss of function?
both
what are the 2 classes of TSGs
gate keepers and care takers
what do gatekeepers do?
stop cells at checkpoints, send defective cells to apoptosis, regultate cell cycle and cell division
what do care taker TSGs do?
DNA repair for maintenance fo genetic stability
name a caregiver gene
BRCA1/2
name 3 really really important tumour suppressor genes
P53, Rb. BRCA1/2
what do cyclins do
they are proteins that allow the cell cycle to continue when phosphorylated
