Genetic Testing for Inherited Cancers
Cancer Genetics Service for Wales
Genetics in the Media
ASCO
The DNA Double Helix
Adenine (A)Adenine (A)
Thymine (T)Thymine (T)
Cytosine (C)Cytosine (C)
Guanine (G)Guanine (G)
BasesBases
Sugar Sugar phosphate phosphate backbonebackbone
Base pairBase pair
There are two types of genetic changes or mutations:
those that are passed down from generation to generation (germ line mutations)
those that happen during the lifetime of a person and are not passed on to the next generation (somatic mutations).
Cancers that can be inherited:
Breast Ovarian Colorectal Other cancers:
Single gene cancer syndromes (e.g. von Hippel-Lindau disease, retinoblastoma)
Rare cancer syndromes (e.g. Li Fraumeni syndrome, Cowden syndrome) where a variety of different cancers occur in the same family.
What other factors influence cancer?
Environment Diet Exercise
Sun protection Safe sex
Availability of healthcare
services (e.g. screening)
Only a minority (5-10%) of cancers are caused by a genetic mutation.
ASCO
BRCA1-Associated Cancers:Lifetime Risk
Possible increased risk of other Possible increased risk of other cancers (e.g. prostate, colon)cancers (e.g. prostate, colon)
Breast cancerBreast cancer 50%50%85% (often early age at onset)85% (often early age at onset)
Second primary breast cancerSecond primary breast cancer 40% 40%60%60%
Ovarian cancerOvarian cancer 15% 15%45%45%
Decision Aids
Green M, Fost N, Becker J, Biesecker B, Laxova R, Cambone P, Newcomb P, and Newcomb P, Breast Cancer Risk and Genetic Testing (CD ROM). 1997, Wisconsin Alumni Research Foundation: Wisconsin.
GREEN: Breast Cancer Risk and Genetic Testing
Decision Aids
Decision Aids
Bromberg J, Schneider KA, Patenaude A, Simmons J, and Corsini E, Predisposition risk education and Information about cancer testing PREDICT (CD ROM). 2003, inflexxion: Newton, MA.
PREDICT
Some common questions
How is cancer inherited? Can inherited cancers skip a generation? If I look like my parent with cancer, does this
make it more likely that I will get cancer too? What does a genetic test actually involve? I want a genetic test but have been told I cannot
have one. What options do I have?