Genetic cancer testing myths, busted

Lindsay Metcalf, MS, CGC

Prisma Health Cancer Genetics Program

Genetic testing has changed a lot since the original genetic test for the BRCA1 and BRCA2 gene mutations became available in 1997. As genetic testing has evolved and grown, it makes sense that myths and misinformation would grow, too. Lindsay Metcalf, genetic counselor, listed several common genetic cancer testing myths, and explained the truth.

Myth #1: Genes for breast cancer only pass down on the mother’s side and aren’t inherited through fathers or sons

“The genes that increase risk for breast cancer are just as common in men as in women,” said Metcalf. “We get half our genes from our mother and half from our father, and men who carry mutations in their genes that can raise breast cancer risk pass them on as well.”

The difference is that men who carry those gene mutations may not have as much of an increased risk to develop certain cancers as women. Still, when looking into your risk for inheriting breast cancer, it’s important to check into the cancer history on both sides of your family.

 Myth #2: Genetic mutations sometimes “skip” a generation

“Simply put, genes cannot skip generations,” said Metcalf. “Our children can only get the genes that we ourselves have to pass down.”

The origin of the myth, according to Metcalf, has to do with how genes increase risks for certain cancers. The cancer itself may not show up in every generation, but the gene mutation that raises the risk will. This phenomenon is called reduced penetrance.

Myth #3: If you resemble one parent more than another, you’re more likely to inherit that parent’s cancer risks

“The genes that can increase our risks for cancer when they mutate are not in any way linked to the genes that determine our outward appearance,” said Metcalf. “They are inherited totally independently!”

Most cancers are not hereditary, but instead occur spontaneously or have risks increased by medical conditions, diet, environment and more. Meeting with a genetic counselor to determine potential inherited gene mutations is much more accurate than looking in a mirror.

Myth #4: If you’re a carrier of a known cancer-causing genetic mutation, there’s nothing you can do about it, so why bother?

“An overwhelming majority of patients who learn that they carry a hereditary cancer gene mutation feel empowered by this information, not discouraged,” said Metcalf. “Having this information on hand allows you and your doctors to take action to either prevent the development of cancer or to find it and begin treating it much earlier.”

Earlier screenings (such as colonoscopies under the age of 40 for those with a family history of colorectal cancers, or early mammograms for those with a family history of breast cancer) and more intensive screening or testing can help make it more likely that your physician will find the cancer early.

In some cases, prevention options like surgery or certain medications may be available to lower the chance of cancer developing at all.

Myth #5: If you don’t have any ‘cancer genes,’ you don’t need to take any further action to prevent cancer

“Negative genetic testing does not always rule out hereditary cancer,” said Metcalf. “Especially if you use direct-to-consumer genetic testing services like 23andMe. Their results won’t be as thorough or accurate, as they can’t test for as much as medical genetic testing can.”

If there is a known hereditary cancer mutation in your family and you had accurate genetic testing to determine that you did not carry that mutation, your cancer risks may be reduced. However, you could still have an above average risk for cancer. In these cases, genetic counselors help you determine which increased cancer screenings are appropriate.

Myth #6: You may be discriminated against by insurance or life insurance companies based on your genetic risks

“Discrimination against those with hereditary cancer genes is illegal,” said Metcalf. “In 2008, the Genetic Information and Nondiscrimination Act was passed by Congress to prevent health insurers and most employers from discriminating against individuals based on genetic testing results.”

The only caveat? Life insurance was not included in that legislation. Currently, it isn’t known if life insurance companies use genetic information when determining if an individual is eligible for life insurance. If patients are concerned, they can obtain their desired life insurance before they proceed with genetic testing.

Myth #7: Genetic cancer testing is way too expensive, especially since insurance doesn’t cover it

“Luckily, many health insurance companies do cover hereditary genetic cancer testing,” said Metcalf. “And even if your insurance company doesn’t, there is financial assistance often available to ensure that finances don’t get in the way of accessing genetic testing.”

If a patient’s insurance does not cover it, ask if a plan is available to help with affordability. In most cases, it shouldn’t cost more than $250 to receive genetic cancer testing. Many patients who are uninsured or underinsured qualify for financial assistance and are able to obtain testing at no cost.