When my healthcare provider (HCP) told me I needed HER2 and BRCA testing, I nodded politely like I totally understood everything she was saying. But, in reality, I had no clue what those letters meant.
BRCA and HER2 were just part of the acronym soup dumped in my lap after I was diagnosed with breast cancer.
But I quickly learned that biomarkers such as BRCA and HER2 are important pieces to the complex cancer puzzle when it comes to understanding and treating the disease.
Cancer biomarkers and the importance of biomarker testing
Cancer biomarkers are proteins, genes and other substances that can be measured to show details about someone’s cancer or cancer risk.
Cancer varies from person to person at the gene or protein level, and biomarker testing can help HCPs create a personalized treatment plan to target the disease — also called precision medicine.
“Some biomarkers help healthcare providers identify the exact type or subtype of cancer. Others help predict whether a patient is likely to benefit from a specific treatment, such as a targeted drug or immunotherapy,” said medical oncologist Leyre Zubiri Oteiza, M.D., Ph.D. “For example, some lung cancers have a change in a gene called EGFR. Patients with this change can receive pills that specifically target that mutation and often work better than standard chemotherapy.”
Biopsies or blood tests for biomarkers can also provide insight into signs of genetic or molecular mutations, how the cancer may behave over time, how aggressive the cancer may be, and/or the risk that the cancer may come back. “Just as important, biomarker testing can help avoid treatments that are unlikely to work, saving time and reducing unnecessary side effects,” Zubiri Oteiza said.
The newest actionable biomarkers in cancer care
The discovery of cancer-specific biomarkers has been a game changer for treating the disease.
“In the past, healthcare providers mostly chose treatments based on where the cancer started in the body, like the lung or breast, and what the cancer looked like under the microscope,” Zubiri Oteiza said. “[Now] some treatments are based on the biomarker rather than where the cancer started.”
Today, there are many biomarkers that are actionable biomarkers, meaning one or more treatments are available to directly target the biomarker to stop cancer growth. “Actionable biomarkers have led to the development of highly effective drugs that can have better outcomes than with traditional chemotherapy,” Zubiri Oteiza said.
One example of an actionable biomarker is an NTRK gene fusion. When this biomarker is present, targeted therapies can block it, regardless of the type of cancer.
“Overall, these advances are helping patients live longer and with better quality of life, while also making cancer treatment more precise and individualized,” Zubiri Oteiza said.
Some of the newest actionable cancer biomarkers include:
- Programmed death-ligand 1 (PD-L1): PD-L1 stops the immune system from attacking cancerous cells in many different types of cancer, including bladder, breast, kidney, stomach, cervical and non-small cell lung cancer.
- Depending on the type of cancer, people with high levels of PD-L1 may respond to immunotherapy called immune checkpoint inhibitors that stop PD-L1 from binding to T cells (white blood cells that destroy cancer cells) and allow the immune system to kill the cancer cells.
- Trophoblast cell surface antigen 2 (TROP2): TROP2 is a biomarker for tumor aggressiveness in different types of cancer, including colon, pancreatic, gastric, breast and non-small cell lung cancer.
- TROP2 is the target of a targeted cancer therapy called antibody-drug conjugates (ADCs).
- Epidermal growth factor receptor (EGFR): When EGFR proteins are mutated or overexpressed, they increase cancer progression in people with lung cancer.
- EGFR is a target for different cancer therapies, including tyrosine kinase inhibitors.
- FLT3-internal tandem duplication (FLT3-ITD): FLT3-ITD is an aggressive genetic mutation that causes rapid cell growth in acute myeloid leukemia and is associated with high relapse rates and poor outcomes.
- FLT3-ITD presence guides personalized treatments to FLT3 inhibitors and early stem cell transplants.
- Human epidermal growth factor receptor 2 (HER2): Cancers with high amounts of HER2 protein or HER2 genes are called HER2 positive and tend to grow and spread quickly to other parts of the body.
- HER2 targeted therapy is used for HER2 positive cancers of the breast, stomach, esophagus, ovaries, pancreas and bladder.
How to talk to your healthcare provider about biomarker testing
Biomarker testing is standard care these days, but it’s important to talk to your HCP about what you can expect and what biomarkers are being considered.
“Your healthcare provider can explain what tests are needed, whether they require tumor tissue or a blood sample, and how the results may guide your treatment plan,” Zubiri Oteiza said. “Sometimes testing is done on the tumor itself during a biopsy and other times it can be done through a blood test called a liquid biopsy.”
It’s a good idea to write down all the questions you have about biomarker testing and go over them with your HCP.
Questions about biomarker testing can include:
- Will I need a tissue biopsy or a liquid biopsy?
- What biomarkers are you testing for?
- Are there any other tests that can measure these same biomarkers?
- How will you use the information to recommend a treatment plan, and will the results change my treatment options?
- Will my insurance pay for biomarker testing? If not, what financial assistance options do I have?
“Being informed and asking questions can help you play an active role in your care and make sure you are exploring all available options,” Zubiri Oteiza said.
This educational resource was created with support from Daiichi, a HealthyWomen member.
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