GIM 5 - Familiar Cancer Syndromes Flashcards
what does landscaper do?
control the surrounding stromal enviroment to prevent cancer formation
what is an example for gatekeepr genes
TP53
In FAP, what type of genes have gone wrong
gatekeeper
In HNPCC, what type of genes have gone wrong
caretaker
what affects the likelihood of developing cancer?
importance of gene function
what does tumour suppressor genes do?
Protects cells from becoming cancerous
loss of function increases risk of cancer
examples for tumour suppressor genes
APC, BRCA1/2, TP53
what does the oncogenes do
regulate cell growth and differentiation
how can tumour form in relation to oncogenes
cause oncogenes to gain function/activate - increase risk of cancer
example for oncogenes
growth and signal transduction factors, RET gene
what is 2 hit hypothesis
2 hits on both allele in order for cancer to form
recessive at ndromcellular level
only one more hit in familial cancer syndrome as one allele already affected
what sort of inheritance pattern does most cancer syndrome show
autosomal dominant
what is missense mutation?
single change in base pair leading to change in protein coding ie mistake
what is nonsense mutation
replacement of a single nucleotides leading to coding for a stop codon
what is frameshift mutation
whole sequence of the aa coded is shifted due to nucleotides changes
when is diagnostic testing carried out?
usually performed on DNA from a relative affected with cancer to try to identify the familial mutation
when is predictive testing carried out?
If a mutation is identified in the family, predictive testing for the specific mutation may then be offered to other relatives to determine whether or not they are at risk
is retinoblastoma inherited?
yes/can be
which gene is affected in retinoblastoma?
retinoblastoma gene (Rb1)
What does FAP stands for
familiar adenomatous polyposis
which cancer is FAP high risk of?
bowel cancer?
what is the pattern of inheritance in FAP?
autosomal dominant
which gene is faulty in FAP?
APC tumour suppressor genes
what does HNPCC stands for?
hereditary non-polyposis colorectal cancer
what sort of genes are faulty in HNPCC
caretaker
what sort of inheritance is HNPCC
autosomal dominant
diagnostic criteria for HNPCC?
One member diagnosed with colorectal cancer before age 50 years
Two affected generations
Three affected relatives, one of them a first-degree relative of the other two
FAP should be excluded
Tumours should be verified by pathologic examination
what does BRAC1/2 do?
DNA repair - caretaker
what are the pattern of inheritance for BRCA1/2
autosomal dominant
which gene is faulty for Li Fraumeni syndrome
P53 - gatekeeper
what sort of inheritance pattern is Li Fraumeni syndrome
autosomal dominant
