Every type of cancer is associated with changes in genes and protein structure or function in the body known as “biomarkers”. These biomarkers can help diagnose cancer, as well as to track the disease and response to treatment. Over the last 10 years, technology has led to the identification of many cancer biomarkers; the use of cancer biomarkers has become an important part in the treatment and management of cancer.
For solid tumors, biomarker testing is usually done on the tumor tissue from a biopsy or surgery. Although testing tumor tissue provides a lot of information, there are some challenges with the process. First, tumor cells can be different even within small tumors. To overcome this, the pathologist (doctor that examines tumor tissue) needs to test cells from different parts of the tumor. Often, there may not be enough of the tissue to test for biomarkers. In addition, tumor cells change when you undergo treatment and there might be a need to repeat biopsies. Sometimes it may not be possible to repeat a biopsy to study the changes in biomarkers because some patients cannot have a repeat biopsy done safely.
There are many advantages to tracking biomarkers in the blood instead of on tissue. We can study changes in biomarkers more often (because it is a blood draw), and therefore will be able to determine how treatment is working, learn if the cancer is coming back, or find drugs that may target the changed tumor cells.
Click on topic below for more information.