Biomarkers are measurable characteristics which indicate a biological state or condition of the body. Biomarkers are discovered in blood, tissue, or bodily fluids and are useful for gaining molecular insights into the status of cancer and other diseases, such as heart disease. In essence, biomarkers are molecular hints at the basis of a disease. Biomarkers are measured using diagnostic tests or assays. Personalized medicine (sometimes called genetic, genomic, precision, or targeted medicine) is a growing medical practice that uses patients’ unique genetic profiles to guide the prevention, diagnosis, and treatment of disease. To determine which patients would benefit from personalized medicine, providers use diagnostic tests to determine if the patient has a biomarker.

Read about ctDNA, a type of cancer biomarker and our efforts surrounding the biomarker here.

Targeted Therapies

Targeted therapies target specific alterations that cancer cells need to persist and spread. While traditional chemotherapy kills cells that multiply quickly, regardless of whether they are cancerous, a targeted therapy favors only cells with a specific alteration that causes cancer without targeting healthy, non-cancerous cells. To determine the appropriate targeted therapy for a patient, a clinician must assess if the patient’s tumor has any relevant biomarkers to target. This is done through diagnostic assays.

For example, trastuzumab is a targeted drug used to treat certain breast cancers. It works by acting on the receptor for a protein called “HER2/neu.” Trastuzumab is only beneficial in cases where patients’ tumors overexpress HER2. Physicians are able to prescribe trastuzumab only for patients who might benefit by using a diagnostic assay to test patients for overexpression of HER2 before recommending trastuzumab.