Development of biofluid-based tests for cancer is an exciting area of innovation that is being enabled by powerful genomic technologies such as digital PCR. These new tests have the potential to dramatically improve tumor characterization and the real-time monitoring of cancer in a minimally invasive fashion.
A noteworthy example was published this week in the open-access journal Molecular Therapy – Nucleic Acids. In this study, researchers from the Massachusetts General Hospital (MGH) and their colleagues demonstrate the use of RainDance’s RainDrop Digital PCR System with other PCR methods to detect a common tumor-associated mutation in the cerebrospinal fluid of patients with brain tumors. The investigators describe the use of these technologies to analyze bits of RNA carried in membrane-covered sacs called extracellular vesicles (EVs) for the presence of a tumor-associated mutation in the IDH1 gene.
Corresponding author Xandra Breakefield, PhD, of the MGH Molecular Neurogenetics Unit said in a statement: “Reliable detection of tumor-associated mutations in cerebrospinal fluid with digital PCR would provide a biomarker for monitoring and tracking tumors without invasive neurosurgery. Knowing the IDH1 mutation status of these tumors could help guide treatment decisions, since a number of companies are developing drugs that specifically target that mutant enzyme.”
While digital PCR has not previously been used to quantify rare mutations at the RNA level or been tested on EV nucleic acids, the authors conclude that it could “provide high-value monitoring of specific subtypes of gliomas in a minimally invasive manner.”
Coauthor Fred Hochberg, MD, of MGH Neurology added, “The current approach for patients who may have a brain tumor is first to have a brain scan and then a biopsy to determine whether a growth is malignant. Patients may have a second operation to remove the tumor prior to beginning radiation therapy and chemotherapy, but none of these treatments are targeted to the specific molecular nature of the tumor. Having this sort of molecular diagnostic assay – whether in spinal fluid or blood – would allow us to immediately initiate treatment that is personalized for that patient without the need for surgical biopsy.”
The full text of the article can be accessed online at the Molecular Therapy – Nucleic Acids website.
The RainDrop Digital PCR System is for Research Use Only; not for use in diagnostic procedures.