Familial Cancer Flashcards
Which enzyme is responsible for transcription of DNA to mRNA?
RNA polymerase
Which process follows transcription to remove introns from mRNA?
Splicing
What is an example of a splicing disorder?
Myotonic dystrophy
Where does translation occur?
Ribosome
What are mRNA and tRNA also known as at the ribosome?
Codons (mRNA) and anticodons (tRNA)
What does translation synthesise?
Polypeptide chain of amino acids
What are exons?
“expressed” sequences that code for proteins
What are introns?
“intervening” sequences that make up 98% DNA
List the 4 abilities a cell has to gain to become cancerous.
- Proliferative signalling
- Avoidance of apoptosis
- Bypassing replicative senescence
- Insensitivity to anti-growth signalling
What is replicative senescence?
Telomere mechanism at tips of chromosome that when too short will stop any further cell division
What is the normal function of a TSG?
Inhibit progression through cell cycle
Promote apoptosis
Act as stability genes
What are some TSGs?
Retinoblastoma (RB)
TP53
NF1
APC
How does mutation affect TSG function?
LOSS of function of protein
How many gene copies must become mutated for the tumourigenic effect, and what is this known as?
2 copies - known as the “two hit hypothesis”
What is the pattern of inheritance of single gene TSG mutations?
Autosomal dominant
What is the normal function of proto-oncogenes?
Stimulate cell cycle
How does mutation affect proto-oncogene function?
GAIN of function of protein - activation to “oncogene”
How many gene copies must mutate to get tumourigenic effect?
1
What are the 2 classes of cancer?
Sporadic
Familial
Which is more common?
Sporadic
Which is earlier in onset?
Familial
Which likely results in a single (as opposed to multiple) primary tumours?
Sporadic
What is normal function of a stability gene?
Minimise genetic alterations (e.g. BRCA1/2)
Which families are considered high risk for breast cancer?
4 cases of breast cancer in individuals under 60yrs
