Geriatrics- Genetic Predisposition to Cancer Flashcards
What % of breast cancers have a family/hereditary link?
Approx. 25%
What % of ovarian have a hereditary link?
5-10%
What % of colorectal cancer have a family/hereditary link?
10-30%
What is the other name for HNPCC which is a bowel cancer syndrome?
Lynch syndrome
Give an example of a cancer caused by a somatic mutation (non-germline).
Breast cancer
->usually happens in one cell, if treated, it’s done. However, sometimes people can have other geneic predispositions to cancer
What type of mutation can cause cancer family syndromes?
Germline mutations.
->these are inheritable
Which two ways in the cell cycle can cause dramatic increase in cell division and therefore cause cancer?
Switch on oncogenes
Switch off tumour suppressor genes
What is retinoblastoma?
A tumour of the retina, caused by lack of tumour suppressor genes
->can be spotted when taking photos with a flash, pupil of eye appears white
What is the main mechanism of action for familial cancer, like Lynch syndrome?
DNA Mismatch Repair
->usually sorted by DNA repair, however, not always noticed
Which cancers are those with Lynch syndrome at increased risks of?
Colorectal
Endometrial
Urinary tract
Gastric
Ovarian
What are some of the clinical features of HNPCC/Lynch syndrome regarding colorectal cancer?
Earlier age at CRC diagnosis
CRC tends to affect right side of colon- this is bad as harder to diagnose. This is because if there is a colon cancer in the left side, there will be bleeding symptoms and constipation.
RECAP- which genes cause a risk of breast cancer?
BRCA1/2
What is important to note about breast cancer relating to BRCA1/2?
Patient more at risk of a secondary breast cancer
There is also an increased chance of ovarian cancer with BRCA1/2. Which gene especially have an increased risk?
BRCA1
In men with BRCA1/2, what impact might this have on them?
Increased risk of prostate cancer
In men with BRCA1/2, what impact might this have on their female offspring?
Increased risk of breast cancer
Which BRCA gene is more likely to cause prostate cancer in men or increase the risks of them passing it onto daughters?
BRCA2
When may you suspect hereditary cancer syndromes?
Cancer in 2 or more close relatives
Early age at diagnosis
Multiple primary tumours
Bilateral or multiple rare tumours
Characteristic patterns of tumours e.g. breast and ovary
What are the most important things to reduce risks of cancers, especially if there is a genetic risk?
Stop smoking
Exercise
Good diet
->much more effective than medicines
Which operation can be done if there is a high risk family history of breast cancer?
Prophylactic mastectomy
->significantly reduces breast cancer risk in women who have the BRAC gene.
Which operation can be done if there is a high risk family history of ovarian cancer in those with BRCA or Lynch syndrome?
Prophylactic oophorectomy and salpingotomy
What is done in those with colorectal cancer gene carriers/Lynch syndrome?
Colonoscopy
Prophylactic aspirin given
In bowel tumours, what can be tested for in the tumour?
Can test the tumour for Lynch syndrome
First degree relatives?
One step away in family tree e.g. siblings, parents
Second degree relatives?
Two steps away in family tree e.g. grandparents, uncles, aunts
Third degree relatives?
Three steps away in family tree e.g. first cousins
In Li-Fraumeni syndrome, there is a high risks of rarer cancers in a family. Give some examples where you would be suspicous.
Family history of many severe cancers.
e.g.
bilateral breast cancer
2 different types of cancer
brain tumours
soft tissue sarcoma, especially in children
leukaemia
early onset breast cancer
->more to just be aware of having high clinical suspicion of these rarer cancers clustering in families
