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Cancer & Genetics: Is It in Your DNA?

July 21, 2016
DNA Strand

Genetic mutations can have helpful, harmful or neutral effects on a person’s overall health. Harmful mutations can increase a person’s chance of developing a disease, including certain types of cancer. With cancer specifically, research indicates that inherited mutations play a role in about 5-10% of all diagnoses. So, can cancer really “run in your family,” and what steps can be taken to lessen that risk?  

Genetics & More

Cancer is a genetic disease, which means that it is caused by certain changes in genes that regulate the way cells function. Genetic changes, also known as mutations, can be inherited from parents and/or acquired during one’s lifetime. Most cancers, however, are not related to a hereditary susceptibility. There are numerous factors that can lead to a diagnosis, including age, environment, hormonal issues, and lifestyle, as well as hereditary causes.  

“People inherit chromosomes, and within a person’s individual genetic makeup, they may have a mutation in a gene that makes them susceptible to a certain type of cancer,” explains Dr. Grace Makari-Judson, medical director of the Family Cancer Risk Program at the Baystate Regional Cancer Program.  

These genetic changes contribute to the development of a disease, but they do not directly cause it. Some people with a predisposed genetic distinction will never get the disease while others with the same distinction will.  

“It is important to clarify that not everyone who inherits a cancer susceptibility gene actually gets cancer. Some of these susceptibility genes may be associated with a 70-80% lifetime risk of cancer, while others may indicate only a 20-40% lifetime risk of cancer,” says Makari-Judson.  

With many hereditary cancer syndromes, the transmission is based on autosomal dominance, which refers to a first-degree relative.

“What that means is that if my mother has a mutation, then there is a 50-50 chance that she can pass it on to her children,” says Makari-Judson. “And, there is a 50-50 chance that her siblings may have inherited the same thing.”  

These genes can be passed down to both male and female offspring. With some types of cancer—such as breast—where men are at far less risk of diagnoses, they can still pass on the mutation to their offspring.  

Genetic Testing & Counseling

So, how does one find out if they are at risk due to genetic factors?  

Genetic testing can be performed to look for specific cancer susceptibility genes if a family history warrants it. Genetic testing, administered as a blood test or buccal swab (on the inside of the cheek), looks for specific inherited changes in a person’s chromosomes, genes or proteins.  

“What is very complex is the counseling to be certain that individuals are informed about the implications of the test results,” adds Makari-Judson. “People need to be well informed when undergoing genetic testing about exactly what they are being tested for and what they might need to do differently if a mutation is found in one of those genes.”  

Appropriate counseling with trained genetic counselors and cancer specialists is important no matter what the test results reveal. Even if there is no mutation identified, a person might still be at higher risk for certain cancers and need to be counseled on risk-reducing strategies. In individuals where a cancer susceptibility gene is identified, a meeting with an oncologist will occur to formulate a plan of monitoring, where certain lifestyle changes may be appropriate.

The Baystate Family Cancer Risk Program is located at 3350 Main Street in Springfield. Phone: 413-794-8890.