Your DNA and Cancer: The Role of Genetics

Is it possible you inherited a faulty gene that puts you in a high-risk category for cancer? Researchers are rapidly uncovering more ties between genetic mutations and cancer, and cancer genetic testing ― now more widely available ― can provide valuable information about your genetic risk and more.

Arelis Mártir-Negrόn, M.D., medical director of Clinical Genetics at Miami Cancer Institute, part of Baptist Health

“This is a fairly new science,” says Arelis Mártir-Negrόn, M.D., medical director of Clinical Genetics at Miami Cancer Institute, part of Baptist Health. “We just celebrated the 20^th anniversary of the Human Genome Project’s sequencing of a complete human genome. The science has moved very quickly, and we are learning more every day.”

To celebrate National DNA Day, Dr. Mártir-Negrόn recently gave an educational talk: The Link Between DNA & Cancer Predisposition. You can watch the free presentation here (code BaptistCancerCare23!).

Every cancer is associated with a genetic change in a cell, but not every mutation causes cancer. For some patients, discovering through genetic testing that they are predisposed to cancer could mean they are able to prevent a specific cancer altogether. For others, it may lead to early detection, thanks to heightened awareness and screening. And for those who do have cancer, genetic testing may help determine the best treatment, such as using a drug with good success at wiping out their type of tumor cells.

Approximately 15 to 18 percent of cancers are now known to be hereditary (caused by a mutation passed down from the biological mother or father, or both). Examples include the BRCA1and BRCA2 mutations, which lead to an increased risk of breast cancer in women and men, ovarian cancer in women and prostate cancer in men; ATM mutations with a higher chance of breast and colorectal cancer along with leukemia and lymphoma; and EPCAM mutations, known to raise the risk of adrenal, bile duct and endometrial cancer.

The genetic teams at Miami Cancer Institute and Lynn Cancer Institute can help patients better understand their risks, determine if genetic testing would be beneficial, and explain the results, whether they are positive, negative or inconclusive. Based on the information, they can also help family members who may be affected.

Dr. Mártir-Negrόn says a cancer genetic assessment should be considered if you are diagnosed with cancer at or under age 50. “We typically think of cancer as a disease of aging,” she says. “As you get older, disease could be the result of a combination of environmental and lifestyle factors that may have accumulated.” But when a person is diagnosed with cancer before age 50, physicians must consider that the disease could be a result of inherited mutations.

Other red flags include:

·       You have multiple primary cancers.

·       There are multiple close family members (in the same family lineage) who have had cancer.

·       You have a rare cancer.

·       Your ethnicity puts you into a high-risk category.

·       Your family has certain combinations of cancers.

·       There are two or more family members on the same side of the family with the same type

        or several types of cancers.

If genetic testing is indicated, the cost is usually covered by insurance. It’s a simple procedure involving samples of blood, saliva or skin that are sent to the lab and analyzed. The results, which once took months to receive, now typically take 10 days or less.

It’s important to meet with a genetic team after testing, Dr. Mártir-Negrόn says, because results may not always be straightforward and genetic testing can be anxiety-provoking. “A positive result means you were found to carry a predisposition, but it doesn’t mean you have cancer or that you will develop cancer,” she says. Cell changes may be benign and not carry a health hazard.

If you believe you are at high risk for hereditary cancer, gather as complete a family history as you can, doctors recommend. Because we each inherit two copies of each gene, one from our mother and one from our father, it’s as important to know your father’s family’s cancer history as it is your mother’s. Then talk to your physician about next steps.

“Testing is very sophisticated and there is a lot of science behind it,” Dr. Mártir-Negrόn says. “Before DNA sequencing, none of this was possible. There is still so much we don’t know, but we are discovering more each day that is improving our ability to prevent, detect and treat cancer.”