Discovering the potential of liquid biopsy
Roche “liquid biopsy” technology can enable tumor markers to be detected through a simple, non-invasive blood draw, making it an ideal complement to tissue biopsy.
For patients with cancer, biopsies provide crucial information on diagnosis and prognosis, as well as enabling predictions about response or resistance to treatment. However, in some diseases, like non-small cell lung cancer (NSCLC), the health of the patient or the location of the tumor make it difficult to resect enough tissue for biomarker testing.
Liquid biopsy is a new testing method that relies on plasma or urine rather than a tissue sample to acquire information about the proteins, nucleic acids and cancerous cells found in a tumor. Plasma is obtained through a simple blood draw, making it non-invasive for patients and easily repeatable for labs and physicians. As a result, liquid biopsy is quickly becoming a compliment to tissue biopsy, with the potential to transform testing and disease management for cancer patients.
The science of liquid biopsy
For several decades, it has been known that tumors release markers into the blood in different ways. Cell-free DNA (cfDNA), circulating tumor cells (CTCs) and exosome mRNA are all increasingly being isolated and used to detect and monitor targets associated with cancer—for diagnosis, prognosis prediction and drug resistance monitoring.
The biggest benefit of liquid biopsies lies in the potential to detect disease progression or treatment resistance long before it would trigger clinical symptoms or appear on imaging scans. In addition, certain cancers, such as melanoma and lung cancers, tend to have at least two to four genetic mutations. The tissue samples removed for biopsy may not show all mutations whereas liquid biopsies offer an improved chance of detecting these genetic changes.
The future of liquid biopsy
More validation in clinical trials is required to better understand the value of liquid biopsies in the medical setting. Targeted therapies do not yet exist for all cancers, nor is it yet clear whether liquid biopsies are the best option for diagnosis, monitoring and informing treatment decisions.
Nonetheless, Roche today offers a test (the cobas® EGFR Mutation Test v2) that uses both tissue and cfDNA in plasma to identify the mutations in the epidermal growth factor receptor (EGFR) gene associated with NSCLC. And as promising research into liquid biopsy continues, Roche remains committed to directly translating that research into more accurate diagnostics and improved patient care.