CLINICAL CANCER GENETICS Flashcards
o How do we detect people who have an increased lifetime risk of developing cancer due to genetic factors? What can we do to reduce cancer risk in people at increased genetic risk?
- Screening
- Prevention
- Early Detection
o This reduces them getting cancer or an advanced incurable cancer.
What is DNA?
A molecule which contains the human genetic code
What are genes?
The instructions to tell the body how to grow, develop and function
Consist of sections of DNA which the cell translates into proteins
~ 20,000 genes in the human genome
2 copies of most genes – one on each chromosome
A section of the genetic code which can be translated into a protein
How long is the human genome?
The entire length of DNA contained in human cells
3 billion bases
How do we have variation?
o We have around 5 million different genetic changes compared to another unrelated person
o Genetic variation makes us unique
o Genetic variation may influence our chance of developing disease
o External factors like smoking, exposure to UV causes a permanent change to the DNA, known as a mutation
o 5 million different genetic changes – these influence how likely you are to get cancer in your life time.
o Vast majority of cancer not due to inheritance, instead it is sporadic, change occurs in replication as. mistakes are made, mutations are acquired everytime cells divide.
What is sporadic cancer?
o Acquired mutations in cancer genes “drive” the cell to become cancerous
o Not inherited changes
How can we have an inherited cancer risk?
o Genetic changes we are born with which increase the risk of developing cancer High risk changes Cancer predisposition genes - cpg Moderate risk changes Low risk changes
Describe the genetic graph
o X axis – how common it is likely to occur in the population
o Genetic changes that cause cancer occur all across the spectrum
o Variants that are common in gen pop, but only one variant only IN by a small amount
o More variants = higher risk
