cancer Flashcards
what is cancer and what is a term for it
abnormal growth of bodies own cells
neoplasm
what is a tumor and what are the two categories they are commonly sorted into
a tumor is localised swelling
the can be sorted into:
benign malignant
what are some features of benign tumors
rarely life-threatening
do not invade neighboring tissue
do not metastasize
what are some features of malignant tumours
maybe life threatening
can invade and destroy nearby tissues
can metastasise
how do cancers metastasise
cancer cells can invade neighbouring tissues, and if those tissues have a blood supply then cells can break away from the tumour and reattach to a different part of the body
these are called secondary tumours
what is an example of a cancer that speads readily and one that barely spreads
melanoma spreads early
glioma barely spreads at all
whats are the primary naming conventions of cancer
most cancers are named for the tissue they originate from
some are named after their discoverer
what are the two major cancers for men and women and what are the cancers asossiated with both groups
prostate(25%), breast(31%)
lung bowel and skin(~10-15%)
what is the age distribution of cancers
two thirds of cancer are over 65s
one third is over 75s
how does cancer proliferate relative to other cells
cancer outcompetes other cells which in large eukaryotic organism is hamrful
what are the exogenous factors that contribute to cancer formation
smoking
diet
sunlight
occupation
viruses such as hpv, ebv
genetic mutation (inherited)
hormone such as glorious glorious estrogen
what are carcinogens and mutagens
carcinogens are substances or radiation that directly cause cancer
mutagens react with dna
what are the two categories of genetic changes that give rise to cancer
proto-oncogenes to oncogenes and inactivation of tumour suppressor genes
where in the body are mutations in cells the most dangerous
is most dangerous in stem cells as they are long lived
what is the car metaphor for cancewr genes
oncogenes drive cancer when activated too much
like a car accelerator
tumour suppressor genes cause cancer when they are turned off or lost (brakes)
what typifies an oncogene from a protooncogene
an oncogene is either active too much or active at inappropriate times
some control cell proliferation
what are the types of mutation that give rise to cancer and what do they do
point mutation: can create a hyperactive or resistant to degradation
Gene amplification: causes growth-stimulating hormone/ protein to be produced in excess
transposition: leads to a new promoter that might overproduce
what are the most specific common mutations in cancer genes
p53 and pik3ca
what is pik3ca
is a lipid kinase which phosphorylates a lipid to make a growth factor
what is p53
a transcription factor that causes cells to stop growing and die under cellular stress and damage
does pi3k mutation increase or decrease the enzyme activity
generally increase in problematic mutations
what can overexpression and amplification do to certain genes and what are some examples
MYC in luekemia and lung cancers
EGFR in cancers such as lung and colon
her2 in breast cancer
what is her2, what cancer does it cause in what percentage
her2 is a gene amplification cancer, it forms breast cancer, and is responsible for about 20% of cases
what is translocation chromosomal mutation
where translocation brings two previous sections of a genome together, its a large scale genomic rearrangement
what are generally the two changes that result in cancer during chromosomal mutation
synthesis of a new fusion protein
inappropriate expression of protein
what causes almost all chronic myloid leukaemia
almost all cml cases are caused by a translocation of bcr onto able protein, causing a unregulated protein tyrosine kinase
what do tumour suppressor genes do in normal cell function
code for protiens for which the normal function makes cancer less likely
if those cells mutate or inactivate, those cells progress to cancer, usually in combination with other cells
what is p53 and why is it called that
named cause the protein has a mass of 53kda
when properly functioning, it binds to promoter sites to prevent transcription
what other things to the tp53 genes do
it can detect dna damage and prevent the progression of the cell through the replication checkpoint
if the damage is minor, replication is halted till repair, if not the apoptosis of the cell is triggered
50% of cancer has a tp53 mutation
how often do mutations happen
slightly less than one every division
what catagories can mutations be split into, relating to their role in driving cancer
driver mutations which cause cancer
passenger mutations are common but do not drive cancer
