What is a Biomarker?

If you or a loved one have been diagnosed with cancer, you have likely immersed yourself in the rich vocabulary of oncology and cancer biology. In your research, you may have encountered the term "biomarker." But what is a biomarker?

A biomarker is any physical characteristic of the human body that can be measured. Your blood pressure is a biomarker. A hemoglobin level is a biomarker. Some biomarkers can be linked to a particular diagnosis, to disease outcomes, or to response to medication or other therapy. In oncology, important biomarkers that can be measured include the DNA, RNA, and protein within a tumor. These biomarkers can be used to make a diagnosis, to predict cancer aggressiveness, or to predict that a particular therapy will be effective.

Measuring cancer biomarkers provide information to guide therapy and predict outcomes

  • DNA (deoxyribonucleic acid) is a molecule inside the cell that carries genetic information and passes it on from one generation to the next.  DNA biomarkers can be evaluated for aberrations such as gene mutations or copy number alterations (e.g. gene amplification) that can cause a cancer cell to proliferate. 
  • RNA (ribonucleic acid) contains information that has been copied from DNA. RNA biomarkers can be interrogated for gene fusions or a clinically relevant variant transcript which are commonly matched with FDA-approved medications. 
  • Proteins are comprised of amino acids.  In normal cells, they support proper body functioning and are the basis of body structures such as skin and hair. In cancer, evaluating protein expression provides information on cancer type, optimal treatment, and can assess treatment efficacy.

Which biomarkers are important to measure? Caris measures a comprehensive set of biomarkers to help Oncologists make informed treatment decisions.

Understanding how Biology Informs Treatment Decision-Making

To the treating oncologist, clinical utility is paramount in managing the cancer patient.  A biomarker with a good track record of clinical validity – i.e. a reliable test – is not enough.  As mentioned, biomarker profiling serves three essential functions:  confirming what the tumor is (diagnosis); getting an idea of the tumor’s aggressiveness (prognosis); and identifying potential vulnerabilities in the tumor (prediction).

Diagnosis

In pathology, evaluating a tumor’s cellular architecture and, if necessary, selecting from amongst established diagnostic markers generally leads to a proper diagnosis.  Interrogating a tumor’s underlying biology may confirm a suspected diagnosis – the sarcoma family of tumors serve as classic examples.  Although uncommon, a new diagnosis is found after a thorough molecular evaluation of a tumor specimen, sometimes dramatically altering the course of management.

Prognosis

Biomarkers used in prognosis determine a malignancies’ likely course (e.g. odds of recurrence).  Should a prognostic biomarker predict for a poor outcome, the treating oncologist may opt for more intensive therapy.

Prediction

Predictive biomarkers are those which select for a specific medication.  In advanced and metastatic NSCLC alone, various biomarkers – EGFR, ALK, ROS1, MET, RET, and PD-L1 – are recommended by the NCCN upon diagnosis for the purpose of treatment decision-making.  These results determine whether a patient receives targeted therapy, immunotherapy, and chemotherapy based on testing results.

Each cancer has a unique molecular profile – knowledge which directs the next course of management.

Assessing Biomarkers Leads to a Precise Treatment Plan

To interrogate these cancer biomarkers, your doctor will need to submit a tumor specimen or bodily fluid to a laboratory that specializes in advanced pathology and molecular profiling services. These testing methods assess biomarkers for the presence or absence of potentially actionable aberrations. 

At our laboratory, our comprehensive approach reveals what is happening at the molecular level of a tumor to effect patient care.  We incorporate the most current technology and marry them to published clinical studies from academic cancer centers across the globe.  We feel this approach provides your doctor invaluable guidance in determining the next course of therapy or, perhaps, consider a novel approach not previously considered.

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