How Genetic Testing Has Improved Cancer Treatment

“We have made a lot of advances when it comes to cancer therapy.”

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Humans have 20,000 to 25,000 genes. These genes are pieces of DNA inside our cells that help make proteins the body needs to function. DNA is basically the genetic “blueprint” in each cell. It’s what makes you, you.

Sometimes, though, genes can become damaged. These gene changes, also called mutations, play an important role in the development of cancer—and how it’s treated.

“The discovery of the genetic impact on tumors has completely changed the way we think of cancer, the way we diagnose it, as well as the way we treat it,” says Rujuta Saksena, MD, hematologist and oncologist in New Jersey. “We have made a lot of advances when it comes to cancer therapy based on our understanding of the genetic changes at the cellular level in cancers and tumors.”

Cancer Treatments Guided By Gene Changes

As researchers learn more about the gene mutations and pathways in a cancer cell that help it grow, new medicines are being developed to fight these changes.

Targeted therapy essentially targets and attacks the mutations responsible for the growth of cancer cells. “A lot of times cancer cells are able to gain advantages and grow because of certain changes at the genetic level, so targeted therapies help kind of streamline treatment options for these patients, and in doing so improve rates of response to cancer therapy,” says Dr. Saksena.

Immunotherapy doesn't target mutations directly, but instead aims to put the immune system into overdrive so that it recognizes cancer and fights it. Immunotherapy tends to be effective for certain cancers with a genetic issue known as microsatellite instability (MSI).

“Our understanding of these pathways can help us and scientists discover new ways to try and not only treat the cancers, but also improve side effects, which can of course positively impact someone's cancer journey by improving quality of life,” says Dr. Saksena

Understanding Genetic Testing 

In order for doctors to know what changes (mutations) a gene has, they might suggest that a patient undergoes genetic testing. “Genetic testing involves looking at an individual's specific DNA to see if there's an abnormality that either caused their current cancer or puts them at risk for future cancer,” says Joseph Pazona, MD, board-certified urologist in Nashville, TN.

There are different ways genetic testing can be done. One way is on the tumor itself. “When cancer is diagnosed, there's a biopsy or a surgical specimen that's looked at under the microscope, and this tissue can be analyzed to detect certain genetic changes,” says Dr. Saksena. The results of this can help doctors determine the best course of treatment for the patient (for example, if they qualify for targeted therapy).

Genetic testing can also be done via blood work or a saliva sample to determine a person’s risk for certain cancers. This might be done if cancer runs in the family.

 “It really depends on what it is that you're looking for in terms of the tumor type or whether it is to help treatment options for a cancer or to determine an individual's risk for future cancers,” says Dr. Saksena.

Is Genetic Testing Right for You? 

“Although there have been incredible advances in the treatment of cancer, there are still only a handful of cancers in which this work has been done. It's very exciting to see in the future how many more breakthroughs we can come up with so we can use this very specific type of treatment to cure more cancers,” says Dr. Pazona.

To assess your cancer risk or to learn if your type of cancer can benefit from targeted therapy or immunotherapy, talk to your doctor. Together, you can decide if genetic testing is right for you.