What Genetics Can Tell You About Your Cancer Risk

October 2, 2019

The human body is a complex machine. The building blocks that hold it together are cells, each of which contains approximately 25,000 genes in which are encoded the biological instructions for building and operating the human body. Therein lies the key to understanding cancer.

According to the American Cancer Society, “Cells become cancer cells largely because of mutations in their genes … We have two copies of most genes, one from each chromosome in a pair. In order for a gene to stop working completely and potentially lead to cancer, both copies have to be ‘knocked out’ with mutations.”

Gene mutations can be either inherited or acquired. When they’re acquired, it’s typically because of environmental factors, like smoking, radiation, hormones and diet. When they’re inherited, it’s because one generation passes abnormal genes to the next.

“Only 5 to 10 percent of cancers are hereditary,” explains Nicole Salvatore, a cancer genetic counselor at Jersey Shore University Medical Center and Ocean Medical Center. “Genetic testing won’t tell us that you have cancer, or that you will have cancer, but it can tell us whether you were born with an increased risk. And based on that risk, we can make recommendations on types of screening or preventive surgery that can be done.”

Which Cancers are Hereditary?

There are four main types of hereditary cancer:

“If multiple people in your family have had one of these cancers, and they were diagnosed under age 50, those are red flags and you should be referred for genetic testing,” explains Nicole, who says late-in-life diagnoses also can be worrisome. “If you have one family member who was diagnosed with a particular type of cancer in their 80s, that in itself is not much of a red flag; if there are multiple people in your family that were diagnosed in their 80s with the same type of cancer, that could be.”

Beyond the “big four,” there are other types of hereditary cancers for which there can be genetic markers. For instance, pancreatic cancer. “It’s now recommended that anyone with a personal or family history of pancreatic cancer should be referred for genetic counseling, regardless of the age it was diagnosed,” Nicole says.

Other cancers that can be hereditary include:

  • Fallopian tube cancer
  • Primary peritoneal cancer
  • Male breast cancer
  • Prostate cancer
  • Stomach cancer
  • Cancer of the small intestine
  • Kidney cancer
  • Brain cancer
  • Cancer of the bile duct

“Lung cancer, head and neck cancers, oral cancers and esophageal cancers typically are not hereditary. But there are very rare cases where they could be,” Nicole continues. “Same with skin cancers. Melanoma can be hereditary, but when it’s in a sun-exposed area it’s less suspicious.”

When it comes to cancer, there are no guarantees regardless of your genetic makeup. If you have a family history of cancer, however, genetic testing could save your life.

“Family history is so important,” Nicole concludes. “If I had just one message to share with the general population, it would be: Talk to your family. Get your family history. If there’s a concern, talk to your doctors and ask for a genetics referral.”

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The material provided through HealthU is intended to be used as general information only and should not replace the advice of your physician. Always consult your physician for individual care.