Every tumor is unique. Mutations occur in the genome of the cell that lead it down its journey to becoming a cancer cell. The mutations that altered one person’s cancer cell, are not likely to be identical to the mutations that occurred in another patient’s cancer cells. This uniqueness is important and is termed a biological signature.
A biomarker is an indicator of a biological condition or pathology. Cancers can have measurable biomarkers that can be assessed by clinical laboratories and then used to aid in the diagnosis or monitoring of cancer. These biomarkers can be genes or proteins. Some common cancer protein biomarkers measured by the lab include cancer antigens such as CA 19-9, CA 15-3, CA-125 and alpha fetoprotein (AFP), among many others. These types of biomarkers are referred to as 'tumor markers' and they are not very specific. These biomarkers are 'generic' proteins that can be present in multiple tumor types and are not specific to individual patients. In contrast, precision medicine biomarkers assess specific mutations and thus, are much more individualized to a specific patient. This more detailed and precise biomarker testing makes it possible, in many instances, to predict a tumor’s response to therapy. So not only does testing help reveal the presence and nature of a tumor, it can suggest the best treatment regimen.
