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Biomarker Testing

Let’s Talk About Biomarker Testing

As part of the diagnosis and classification of brain tumors, biopsied samples or surgically resected portions of a tumor may undergo a process called biomarker testing. Biomarker testing, as part of obtaining a more comprehensive brain tumor diagnosis, is a way for your medical team to gather as much information as possible about your tumor.

Your biomarker testing results can help shed light on treatment options that may be available to you, including clinical trials. When you know your tumor’s biomarkers, you can make informed decisions about what to do next. Explore key questions, important terms, and other educational resources about biomarker testing to help you make informed decisions as you navigate your brain tumor experience.

Key Questions to Ask About Biomarker Testing

National Brain Tumor Society curated a collection of important questions to ask about biomarker testing. We encourage you to bring these questions with you to your next appointment.

  • What is the difference between pathology and biomarker testing?
  • How would biomarker testing inform my diagnosis, prognosis, and treatment options?
  • How can I get a sample of my tumor tested for biomarkers to learn if any targeted therapies might treat my tumor type
  • Which biomarkers should be tested for my tumor type? Can you explain how they might affect my response to treatment?
  • Will you use the 2021 WHO Classification of CNS Tumors to diagnose my tumor?
  • Is there enough tumor tissue for biomarker testing?
  • Does insurance cover the costs for biomarker testing? If not, is there financial assistance available?
  • How long does it take to get biomarker testing results back?
  • How will my biomarker results be communicated to me? 
  • Who will review my results with me when they are available?
  • My tumor is considered inoperable. Is biomarker testing still an option?
  • Will my biomarker testing be done by a blood test or tissue biopsy?
  • Will next generation sequencing (NGS) be used for my biomarker testing? 
  • How might my biomarker results influence my prognosis?
  • Are there targeted therapy drugs, immunotherapies, clinical trials, or other treatments I might be eligible for based on the results of my biomarker tests? If yes, what is this drug or treatment called, and do you recommend it?
  • How can I enroll in a clinical trial?
  • Can you recommend any reliable sources where I can learn more about my specific biomarkers? 
  • Are there any organizations that may be able to provide additional information about my specific biomarkers?

Key Terms to Know About Biomarker Testing

Explore our list of important terms to know as you familiarize yourself with biomarker testing.

A biomarker, or biological marker, is a characteristic of the body that is a sign of a normal or abnormal process, condition, or disease. Biomarkers can be used in the diagnosis, prognosis, monitoring, and/or treatment selection of different conditions and diseases, such as brain and spinal tumors.

Biomarker Testing
Biomarker testing, also called molecular testing, somatic testing, and tumor profiling, is a laboratory test used to analyze tissue, blood, or other bodily fluids for specific mutations, gene alterations, proteins, and/or other biomarkers. Biomarker testing of brain and spinal tumors can help individuals and their care teams identify the correct diagnosis, prognosis, and appropriate treatment options. Biomarker testing can involve single analyte tests, which examine a single biomarker; multiple-analyte panels, which examine a set of biomarkers; and more complex tests, such as next-generation sequencing (NGS). 

A biopsy is a medical procedure to remove a sample of tissue or cells so that it can be examined by a pathologist. The pathologist may study the sample under a microscope and/or perform other tests, such as biomarker testing.

A biospecimen is a sample of tissue, blood, or other bodily fluid.

A gene is the basic unit of inheritance. Genes are pieces of DNA passed from parents to children that contain the information needed to specify physical and biological traits. 

Genetic Testing
Genetic testing is the use of a laboratory test to examine an individual’s DNA. In the medical setting, genetic testing may be used to determine a person’s risk of developing a disease or condition or having a child with the disease or condition; this type of genetic testing is considered genetic testing for inherited risk. Genetic testing performed on tumor tissue that helps diagnose, prognose, and plan treatment is called biomarker testing.

Genetic Testing for Inherited Cancer Risk
Genetic testing for inherited cancer risk, also called germline testing, is a laboratory test that can show if an individual has inherited a genetic change that increases their risk of cancer. While cancer itself cannot be passed down from parents to children, a genetic change that increases the risk of cancer can be passed down if it is present in the parent’s egg or sperm cells.

A tumor grade is a number used to describe how abnormal the tumor cells and tissue look under a microscope when compared to healthy cells and tissue. Grades can be 1, 2, 3, or 4, with lower numbers considered “low-grade” tumors and higher numbers considered “high-grade” tumors. Low-grade tumors tend to appear more like healthy cells and tissue under a microscope. High-grade tumors tend to appear more abnormal and disorganized under a microscope.

Histopathology is the study of tissue or cells under a microscope to look for the presence of disease.

A mutation is a change in one’s DNA that can result from a random mistake or exposure to a substance, organism, or agent capable of inducing changes in DNA. Mutations can cause a harmful, beneficial, or neutral effect on the individual. Mutations that occur in germ cells like egg and sperm cells are called germline mutations and can be passed on to one’s children. Mutations that occur in other cells of the body are called somatic mutations and are not passed on.

Next-generation Sequencing
Next-generation sequencing, abbreviated NGS, is a newer technology used to sequence DNA and detect mutations that is faster and less expensive than the earlier, first-generation method. For people with brain and spinal tumors, next-generation sequencing can help care teams identify the diagnosis, prognosis, and treatment options.

Precision Medicine
Precision medicine, also called personalized medicine or individualized medicine, is an approach that uses information about an individual’s genes, environment, and lifestyle to guide decisions related to their medical management. Biomarker testing can help care teams determine a more precise diagnosis and determine targeted treatment options for people with brain and spinal tumors.

WHO Classification of Tumours
The WHO Classification of Tumours, also known as the WHO Blue Book, provides an evidence-based classification system of tumors to standardize diagnosis and improve patient care worldwide. The 2021 WHO Classification of Tumors of the Central Nervous System, the current gold standard for brain and spinal tumors, emphasizes the importance of an integrated diagnosis, which layers information about the tumor’s histopathology, grade, and biomarkers.


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Biomarker testing drastically changed everything. Before the testing came back, we didn’t plan to do radiation or chemo because our neuro-oncologist thought it was low-grade. However, he sent it for testing because there are a lot of tumors that look good through imaging and initial pathology but are like a wolf in sheep’s clothing. The tumor ended up more aggressive than they thought, so we had to do radiation and chemo.

Jenny B.

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