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?