Predisposition to Cancer Flashcards
What are the features of germline mutations?
Present in egg or sperm
Are heritable
Cause cancer family syndromes
What are the features of somatic mutations?
Occur in non germline tissues
Non heritable
What are oncogenes?
Mutation of normal gene that leads to accelerated cell division
What are tumour suppressor genes?
1st mutation causes susceptible carrier
2nd mutation leads to cancer
What is hereditary non polyposis colorectal cancer?
Mutation in mismatch repair genes
Excess of colorectal, endometrial, urinary tract, ovarian and gastric cancers
What are the clinical features of HNPCC?
Adenoma-carcinoma sequence for polyp formation
Tumour site in proximal colon predominates
What is the lifetime risk for BRCA1 and 2 associated breast cancer?
60-80%
What is the lifetime risk for BRCA 1 and 2 associated ovarian cancer?
20-50%
What are the features of autosomal dominant inheritance?
Each child has 50% chance of inheriting mutation
No skipped generation
Equally transmitted by men and women
When should hereditary cancer syndrome be suspected?
Cancer in 2 or more close relatives (on same side of family)
Early age at diagnosis
Multiple primary tumours
Bilateral or multiple rare cancers
Characteristic pattern of tumours (breast and ovarian)
Evidence of autosomal dominant transmission
What are the breast cancer surveillance options?
Early clinical surveillance 5yr
What are the benefits of genetic testing?
Identifies highest risk
Identifies non-carriers in families with a known mutation
Allows early detection and prevention strategies
May relieve anxiety
What are the risks and limitations of genetic testing?
Does not detect all mutations
Continued risk of sporadic cancer
Efficacy of interventions variable
May result in psychological or economic harm
