Biomarker 101: How Testing Can Change Cancer Outlook

Gautam Rajpal
October 6, 2023

Cancer affects every patient differently, and each has a unique set of biomarkers. This makes the disease complex and often difficult to predict and treat. Early detection, prevention, and proper diagnosis can significantly impact a cancer treatment plan and help improve patient outcomes. Biomarker testing plays a substantial role in achieving these superior outcomes.

What is a Biomarker? 

According to the National Cancer Institute, a biomarker is “a biological molecule found in blood, other body fluids, or tissues that is a sign of a normal or abnormal process, or of a condition or disease.” 

Different types of biomarkers allow scientists to glean information and make treatment recommendations for each individual. Some of these changes can be seen internally and non-invasively through fluid testing or imaging. Other biomarkers can be obtained through the biopsy of tissue or can be determined by physical changes in the body. 

The most common types of biomarkers are: 

  • Genetic biomarkers: Mutations in a person's DNA that may be associated with a particular disease or condition. These are inherited mutations that are passed down by your parents.
  • Molecular biomarkers: Specific proteins, enzymes, or other molecules that may be present at higher or lower levels in people with a particular disease or condition.
  • Phenotypic biomarkers: Physical characteristics or changes in a person's body that may be associated with a particular disease or condition.
  • Imaging biomarkers: Changes in a patient’s medical imaging, such as changes in the size or shape of an organ, that may be associated with a particular disease or condition.

Biomarkers can be used in a variety of medical fields, including cancer, cardiovascular disease, and neurodegenerative diseases. They can help determine the presence and severity of a disease and are essential in predicting the efficacy of certain treatments.

Biomarker Testing in Cancer

In cancer research, biomarkers can be especially helpful in risk assessment, screening, diagnosis, prognosis, predicting response to treatment, and monitoring the progression of the disease.

According to the National Cancer Institute, other names for biomarker testing that a care team might use include: 

  • Tumor testing 
  • Tumor genetic testing 
  • Genomic testing or Genomic profiling
  • Molecular testing or Molecular profiling 
  • Somatic testing 
  • Tumor subtyping 

Because of this testing, biomarkers help healthcare professionals more accurately evaluate a biopsy to determine whether the tissue is cancer, infected, or inflamed. They can then recommend a more personalized treatment plan.

One of the impactful uses of biomarker testing in cancer is the increased level of precision of care in treatment plans. Using biomarkers and other tests helps your care team select treatments that are most likely to help their patients, while at the same time sparring them from getting treatments that are not likely to help. 

Biomarkers are also used in achieving early detection and predicting potential disease in high-risk cancer patients or in otherwise healthy individuals. 

Testing can also help cancer patients to find new treatments through clinical trials. Biomarker testing can determine which clinical trials a patient may be eligible for. Other times, biomarker testing is part of the study itself to match patients to treatments based on changes reported. 


Limitations of Biomarker Testing

Biomarker tests can be informative, but they may not provide the same assistance to every patient’s treatment plan. Certain medications and treatments may not respond the same way for each patient. 

In addition, certain treatments might be effective on some of a patient’s cancer cells, but not all. Or, a patient’s cancer cells may change over time. Think of biomarker testing as a “snapshot’ of a patient’s cells, which may need to be done multiple times to create an accurate treatment plan. 

Biomarker testing plays a critical role in improving cancer outcomes through early detection, personalized treatment planning, and monitoring treatment response. It is important to talk with your care provider to discuss if biomarker testing should be part of your treatment plan. Check to see if your care provider offers biomarker testing, or if they or a cancer navigator can recommend a place to get this cancer care. 

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