Genetic testing may detect cancer risk

Published Oct 5, 2017 at 12:00pm

Cancer affects people from all walks of life. While there is no guaranteed way to prevent cancer, genetic testing can help individuals better understand their risks for certain types of cancer. 

Genetic testing has been developed for many diseases. Such testing looks for specific markers that can indicate the likelihood that a person will develop a specific disease. Genetic testing has been used to diagnose genetic disorders such as muscular dystrophy and fragile X syndrome. Genetic testing also is used to raise awareness about risk factors for Down’s syndrome. 

Since cancer sometimes appears to run in families, people with a family history of the disease may benefit from hereditary testing. Some genetic tests examine rare inherited mutations of certain protective genes that may be indicative of cancers of the breast or ovaries. These genes include BRCA1 and BRCA2. The National Cancer Institute says mutations in genes that control cell growth and the repair of damaged DNA are likely to be associated with increased cancer risk.

It’s important to note that even if a cancer-predisposing mutation is present in your family, you will not automatically inherit the mutation. And even if you do, it is no guarantee that it will lead to cancer. 

The NCI says that mutations in hereditary cancer syndromes are inherited in three ways: autosomal dominant, autosomal recessive and X-linked recessive inheritance. Autosomal dominant inheritance occurs when a single altered copy of the gene is enough to increase a person’s chances of developing cancer. Autosomal recessive inheritance occurs when a person has an increased risk of cancer only if he or she inherits an altered copy of the gene from each parent. A female with a recessive cancer-predisposing mutation on one of her X chromosomes and a normal copy of the gene on her other X chromosome is a carrier but will not have an increased risk of cancer. Two mutations makes her more likely to get cancer. Men are less likely to get cancer from this mutation because they only have one X chromosome.

Researchers continue to develop tests to examine multiple genes that may increase or decrease a person’s risk for cancer. Such tests may facilitate a proactive approach that can detect cancer before it spreads. 

If you feel you are a candidate for genetic testing, speak with your doctor. Risk is based on things like personal medical history and family history. Testing may be conducted by a trained doctor, nurse or genetic counselor. Patients will go through some sort of genetic counseling and be asked a number of questions about their lineage and the family history of the disease in different branches of their family trees, which will help to determine if further testing is warranted. 

Testing may be done on a sample of blood, cheek cells, urine, hair, amniotic fluid, or other bodily tissues. Results will be interpreted by experts, and the information will be shared. Remember, an increased risk for cancer does not guarantee that you will get cancer. However, it can help you make certain lifestyle choices and become aware of symptoms so that cancer can be caught early. Doctors can help you sort through your options at this point.

Individuals should speak with their doctors about their concerns regarding cancer genetics and potential mutations that may be indicative of heightened cancer risk.