There is a significant cancer family history in about 5 to 10 percent of families. Genetic testing is available to some individuals with this type of family history. Cancers that have specific genes associated with family history include breast, ovarian, colon, melanoma, thyroid, kidney, and retinoblastoma. Prior to any genetic testing, it is strongly recommended that an individual see a genetic counselor or other health professional with expertise in genetics to learn about the risks, benefits and limitations for gene testing for the cancer in their family. Below are questions and answers that are frequently addressed during genetic counseling for cancer gene testing.

On this page:

• How are cancer genes inherited?
• Can anyone have a gene test for cancer?
• What are some of the benefits of gene testing for cancer?
• What are some of the risks and limitations of gene testing for cancer?
• Who should in a family history of cancer?
• Is it still possible to have a gene test for cancer even if I don't have any living relatives with cancer?
• If a gene is identified in my family and I don't have that gene, does this mean that I won't have cancer?
• If I test gene positive, what does this say about my risk of developing cancer?

How are cancer genes inherited? 

Cancer gene mutations (changes) are inherited in families in a dominant pattern. This means that if a parent (mother or father) has a gene mutation that predisposes individuals to cancer, each child, male or female, has a 50 percent chance of inheriting the same gene change. 

Can anyone have a gene test for cancer? 

At this time, it is usually only appropriate to test individuals with a family history. However, there are exceptions and that is why anyone interested in gene testing should contact a genetics clinic in their area. 

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What are some of the benefits of gene testing for cancer?

Gene testing can explain the reason for the cancer in the family. It may also reduce anxiety about whether or not an individual is at high risk for cancer. Genetic test results can be used to develop screening guidelines for individuals. 

What are some of the risks and limitations of gene testing for cancer?

The gene test doesn't test for all types of cancer or all cancer genes. The test is expensive, ranging from $300 to $3000. Gene testing may affect insurance or employment opportunities. This issue is still not resolved. Confidentiality is another related concern. Gene testing may create more anxiety and problems with family members if a gene change or mutation is identified in the family. Not everyone may want this information. 

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Who should be tested in a family history of cancer? 

It is best to test an individual who has already had cancer. 

Is it still possible to have a gene test for cancer even if I don't have any living relatives with cancer? 

Yes, the results for a positive test will still be accurate, but a negative test needs careful interpretation by a health professional with expertise in genetic testing for cancer. 

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If a gene is identified in my family and I don't have that gene, does this mean that I won't have cancer? 

No, this means that you are no longer at high risk, but you are still at population risk of developing cancer. 

If I test gene positive, what does this say about my risk of developing cancer?

This means that you may have a high risk of developing cancer depending on the cancer gene mutation that is identified in your family. In some situations with specific genes, there is documentation that individuals who have an inherited gene mutation for cancer do not always develop cancer. 

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