What to Know About Biomarker Testing for Lung Cancer

5 min read

What to Know About Biomarker Testing for Lung Cancer

Thanks to advances in science, doctors better understand the human DNA and changes that occur over our lifetimes, called mutations. Some of these genetic mutations can lead to non-small cell lung cancer. 

Until recently, oncologists used information such as the size, grade, and location of the cancer to develop non-small cell lung cancer treatment plans. Today it’s possible to identify genetic mutations in non-small cell lung cancer patients that can be treated with categories of drugs called targeted therapy and immunotherapy. To determine if any genetic mutations are present, a process called biomarker testing is used. 

Biomarkers: What Are They and How Are They Identified? 

Biomarkers, short for biological markers, are genes, proteins, hormones, or other substances found in cancer cells, surrounding tissue, and bodily fluids like blood. Sometimes called molecular markers, biomarkers provide important information about the characteristics of the cancer. 

It's important to note that not all lung cancers are the same, even within the category of non-small cell lung cancer. This made it challenging to choose the right treatment plan — what works for one patient might not work for another. By using biomarker testing, also referred to as genomic testing or molecular testing, the oncologist can focus on treating the specific genetic change or changes that are fueling the cancer’s growth. 

Tests are run on the tissue taken during a biopsy or surgery. A report is provided that lists any genetic changes and overgrowth of proteins in a “tumor profile.” This knowledge allows the medical oncologist to tailor a treatment plan specific to each patient’s needs based on the unique characteristics of the tumor. 

Download Lung Cancer Guide for Newly Diagnosed Patients

Biomarker Testing for Lung Cancer Treatment Planning

Lung cancer biomarkers are mainly used to diagnose and treat non-small cell lung cancer (NSCLC), the most common of the two main types of lung cancer. These biomarkers show whether particular proteins and mutations are present in the tumor. Typically, these mutations develop over the patient’s lifetime and are not inherited. In the case of lung cancer, mutations in DNA are related to things like smoke inhalation and other environmental exposures. However, there are lung cancer patients who have no history of smoking or living with a smoker.

There are two primary types of lung cancer biomarkers: 

  • Mutations that encourage cancer cell growth. These may be treated with a targeted therapy if one is available.
  • Immune response biomarkers. These tell the oncologist how likely the cancer is to respond to immunotherapy drugs.

Several biomarkers are associated with non-small cell lung cancer (NSCLC), but the most common one is called tumor protein p53 (TP53). This protein is present in approximately 50% of individuals with non-small cell lung cancer.

The second most common biomarker for lung cancer is KRAS, which is found in around 30% of NSCLC patients. Even though these two biomarkers are the most common, several others are known to be related to lung cancer. If found, drugs are now available to counter many of these mutations.

Read more in our blog Lung Cancer Gene Mutations: What Are They and How Do They Affect Treatment? 

Precision Medicine for Non-Small Cell Lung Cancer

Based on tumor biomarkers, the medical oncologist will be able to develop a treatment plan that is unique to the patient. Treating cancer based on genetics or mutations is called precision medicine, also called personalized medicine. Most of the targeted therapies and immunotherapies approved for non-small cell lung cancer are for patients whose cancer has returned or has developed in other areas of the body.

If there are no genetic mutations found, treatment is still available, although the plan may not include targeted therapy or immunotherapy. The lung cancer specialist may also recommend a clinical trial. It’s possible to access some new therapies or different use of therapies approved for use only in some patients, before they’re available to everyone through the trial. 

Learn more about lung cancer clinical trials at Rocky Mountain Cancer Centers.

Targeted Therapies for Non-small Cell Lung Cancer

Several types of targeted therapy are available for lung cancer treatment. Some of the most common include:

  • Angiogenesis inhibitors - Slow the growth of blood vessels, starving the cancer cells of the blood needed to grow.
  • KRAS inhibitors - Slow the overgrowth of the KRAS G12 protein, which fuels lung cancer cells. This mutation is often immune to the effects of other targeted therapies. 
  • Epidermal growth factor receptor (EGFR) inhibitors - Block the signal from the EGFR protein on the surface of the cells so they cannot continue growing.
  • ALK inhibitors - Found more often in non-smokers, this gene’s rearrangement can produce an abnormal ALK protein that causes cancer cells to grow and spread. The inhibitor drugs slow or stop the production of the abnormal protein. 
  • ROS1 inhibitors - Similar to the ALK rearrangement, the ROS1 rearrangement produces an abnormal protein that causes lung cancer cells to grow. Some of the same drugs that work for ALK also work for ROS1 mutations.
  • BRAF inhibitors - If the BRAF gene has mutated, a targeted therapy used for this and other mutations can be used to slow the production of cancer-causing protein.
  • RET inhibitors - If the RET gene is rearranged, a targeted therapy can be used to slow the production of proteins that fuel lung cancer.
  • MET inhibitors - If a MET exon 14 skipping mutation is found, it’s likely causing an abnormal form of the MET protein that leads to cancer growth which can be targeted with a specific drug. 

There are additional targeted therapies for specific, less common mutations that the medical oncologist will review before recommending a treatment plan. 

Immunotherapy for Non-small Cell Lung Cancer

Cancer cells are often able to “hide” in the body, acting like healthy cells. Checkpoint inhibitors are immunotherapy drugs that target proteins on the surface of the cells that cause cancer cells to turn off their defense. Part of biomarker testing is to see if there are proteins fueling the cancer’s growth and then an immunotherapy drug known to counter it.

What to Do After a Lung Cancer Diagnosis?

If you’re newly diagnosed with lung cancer or have lung cancer that has returned, your oncologist is likely to run biomarker tests to see if there are specific treatments that would be most effective for you. Other treatments may begin, such as chemotherapy or radiation therapy, to slow the growth of the cancer cells. Targeted therapies and immunotherapies can be added when the biomarker test results are available. Your oncologist will know which are approved and available for use in your treatment plan. 

Rocky Mountain Cancer Centers offers the latest lung cancer treatments in Colorado at offices throughout the Front Range. You can request an appointment for a consultation or a second opinion at a location that’s convenient for you.

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