You’ve heard the term “biomarker” in our news before, and it’s gained particular attention among cancer researchers. You may even have heard how cancer biomarkers have played a role in a patient’s decision to seek out preventative surgery.

But, you might be wondering, what exactly is a biomarker? And, why are biomarkers important to cancer research and patient treatment? This is what we’ll cover in today’s post.

First, the definition

A characteristic that is objectively measured and evaluated as an indicator of normal biologic processes, pathogenic processes, or pharmacologic responses to a therapeutic intervention.


Biomarkers give us measurable information about a person’s biological state. This information is objective and reproducible and, in many cases, can be examined from outside of the body. Your weight, blood pressure and blood types are examples of measurable biomarkers that are used on a day-to-day basis to provide information about your health. On a deeper level, biomarkers are also used to tailor specific medical treatments. For example, in order for an organ transplantation to be successful, it is essential to match the patient’s biomarkers with those of the donor organ.

How biomarkers tell us about cancer

There are specific biomarkers that can be used to determine a person’s risk of developing cancer, to follow in real time the progression of cancer, and to determine whether or not a therapy may work to treat a specific cancer, which is the objective of personalized medicine in cancer.

  1. Risk of developing cancer
    Certain markers are inherited and predict a high risk of developing cancer in a healthy patient. A well-known example is BRCA1 and BRCA2, which if inherited from a parent, dramatically increase the chances of developing a certain form of breast cancer.
  2. Following progression of a cancer
    Certain markers are signatures of certain types of cancer, and the levels of these markers are used to follow the disease’s progression and to follow the effectiveness of therapy. Examples include PSA for prostate cancers and CA-125 for ovarian cancers.
  3. Personalized medicine in cancer
    Certain markers are predictive of whether a therapy will work or not for a specific patient. Examples include mutant KRAS in colorectal cancer (which indicates that certain drugs should not be used to treat that cancer in that patient) and mutant VEGF and EGFR in a variety of cancers (which indicate the use of certain drugs to treat the cancer in that patient).

Biomarkers are changing the way cancer treatments are planned

Many clinical studies being run today, including Oncolytics’ ongoing randomized studies (GOG-0186H, IND 209,IND 210, IND 211 and IND 213) are enrolling patients with various biomarker profiles in order to learn which specific profiles can be used to predict treatment success. This information will then be used in future studies to pre-screen potential patients, with the goal of enrolling only those patients with biomarker profiles that are expected to respond to the treatment.

A patient’s first treatment is their best hope of success; having a therapy that is matched to that patient’s cancer maximizes this best hope.